Exhibit 8.1

SUBSIDIARIES

|NAME                                     |  | JURISDICTION OF
INCORPORATION OR
ORGANIZATION
|---------------------------------------- |  | ---------------------------------------------
|99.999 LIMITED                           |  | ENGLAND AND WALES                            
|ADVANTICA CORPORATE VENTURES LIMITED     |  | ENGLAND AND WALES                            
|ADVANTICA LIMITED                        |  | ENGLAND AND WALES                            
|ADVANTICA PTY LIMITED                    |  | AUSTRALIA                                    
|ADVANTICA, INC.                          |  | DELAWARE                                     
|AEMC, L.L.C.                             |  | DELAWARE                                     
|AERIAL GROUP LIMITED                     |  | ENGLAND AND WALES                            
|AERIAL UK LIMITED                        |  | ENGLAND AND WALES                            
|AGL SYSTEMS INTERNATIONAL LIMITED        |  | ENGLAND AND WALES                            
|AMPLE DESIGN LIMITED                     |  | ENGLAND AND WALES                            
|ARBUCKLE ACRES, INC                      |  | NEW YORK                                     
|ARTERION LIMITED                         |  | ENGLAND AND WALES                            
|ASSETHALL LIMITED                        |  | ENGLAND AND WALES                            
|ATLANTIC WESTERN CONSULTING, INC.        |  | MASSACHUSETTS                                
|BASSLINK PTY LIMITED                     |  | AUSTRALIA                                    
|BEEGAS NOMINEES LIMITED                  |  | ENGLAND AND WALES                            
|BLACKWATER 1 LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER 2 LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER 3 LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER 4 LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER 5 LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER A LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER AGENCY LIMITED                |  | ENGLAND AND WALES                            
|BLACKWATER B LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER C LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER D LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER E LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER F LIMITED                     |  | ENGLAND AND WALES                            
|BLACKWATER G LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER H LIMITED                     |  | UNITED KINGDOM                               
|BLACKWATER J LIMITED                     |  | ENGLAND AND WALES                            
|BLACKWATER SC 1 LIMITED                  |  | SCOTLAND                                     
|BLACKWATER SC A LIMITED                  |  | SCOTLAND                                     
|BRITISH TRANSCO CAPITAL, INC.            |  | DELAWARE                                     
|BRITISH TRANSCO FINANCE (NO 1) LIMITED   |  | CAYMAN ISLANDS                               
|BRITISH TRANSCO FINANCE (NO 2) LIMITED   |  | CAYMAN ISLANDS                               
|BRITISH TRANSCO FINANCE (NO 3) LIMITED   |  | ENGLAND AND WALES                            
|BRITISH TRANSCO FINANCE (NO 5) LIMITED   |  | ENGLAND AND WALES                            
|BRITISH TRANSCO FINANCE, INC.            |  | DELAWARE                                     
|BRITISH TRANSCO INTERNATIONAL FINANCE BV |  | NETHERLANDS                                  
|BSC CO LIMITED                           |  | ENGLAND AND WALES                            
|COGSYS LIMITED                           |  | ENGLAND AND WALES                            
|CONTIGUOUS LIMITED                       |  | ENGLAND AND WALES                            
|CROWN CASTLE COMMUNICATIONS LIMITED      |  | ENGLAND AND WALES                            
|CROWN CASTLE UK FINANCE PLC              |  | ENGLAND AND WALES                            
|CROWN CASTLE UK HOLDINGS LIMITED         |  | ENGLAND AND WALES                            
|                                         |  |                                              

---



|CROWN CASTLE UK LIMITED                             |  | ENGLAND AND WALES     
|--------------------------------------------------- |  | ----------------------
|CROWN CASTLE UK PENSION TRUST LIMITED               |  | ENGLAND AND WALES     
|EASTLANDS (BENEFITS ADMINISTRATION) LIMITED         |  | ENGLAND AND WALES     
|EASTLANDS LIMITED                                   |  | ENGLAND AND WALES     
|ELECTRACOM LIMITED                                  |  | ENGLAND AND WALES     
|ELEXON LIMITED                                      |  | ENGLAND AND WALES     
|ENERGI LIMITED                                      |  | ENGLAND AND WALES     
|ENERGIS POLSKA SP. Z O.O.                           |  | POLAND                
|ENERGIS SERVICES LIMITED                            |  | ENGLAND AND WALES     
|ENERGY MARKET OPERATIONS LIMITED                    |  | ENGLAND AND WALES     
|ENERGY SETTLEMENTS AND INFORMATION SERVICES LIMITED |  | ENGLAND AND WALES     
|EUA BIOTEN, INC.                                    |  | MASSACHUSETTS         
|EUA ENERGY INVESTMENT CORPORATION                   |  | MASSACHUSETTS         
|EUA/FRCII ENERGY ASSOCIATES                         |  | UNITED STATES         
|FASTNET CALOOSAHATCHEE COMMUNICATIONS LIMITED       |  | BRITISH VIRGIN ISLANDS
|FULCRUM CONNECTIONS (EMPLOYERS) LIMITED             |  | ENGLAND AND WALES     
|FULCRUM CONNECTIONS LIMITED                         |  | ENGLAND AND WALES     
|GAS RESEARCH & TECHNOLOGY CENTRE LIMITED            |  | ENGLAND AND WALES     
|GEMSTONE SOFTWARE LIMITED                           |  | ENGLAND AND WALES     
|GRAIN LNG LIMITED                                   |  | ENGLAND AND WALES     
|GRANITE STATE ELECTRIC COMPANY                      |  | NEW HAMPSHIRE         
|GRID INTERNATIONAL LIMITED                          |  | ENGLAND AND WALES     
|GRID INVESTMENT HOLDINGS LIMITED                    |  | ENGLAND AND WALES     
|GRID ONE LIMITED                                    |  | ENGLAND AND WALES     
|GRIDAMERICA HOLDINGS INC.                           |  | UNITED STATES         
|GRIDAMERICA LLC                                     |  | UNITED STATES         
|GRIDCOM (UK) LIMITED                                |  | ENGLAND AND WALES     
|GRIDCOM AERIAL SITES PLC                            |  | ENGLAND AND WALES     
|GRIDCOM LIMITED                                     |  | ENGLAND AND WALES     
|GRIDMET LIMITED                                     |  | ENGLAND AND WALES     
|GRIDNAT LIMITED                                     |  | ENGLAND AND WALES     
|GRTC LIMITED                                        |  | ENGLAND AND WALES     
|HUDSON POINTE, INC                                  |  | NEW YORK              
|INFRASTRUCTURE TECHNOLOGY GROUP LIMITED             |  | ENGLAND AND WALES     
|INTERNATIONAL POWER SYSTEMS LIMITED                 |  | ENGLAND AND WALES     
|IPS LIMITED                                         |  | ENGLAND AND WALES     
|ITG LIMITED                                         |  | ENGLAND AND WALES     
|LAND MANAGEMENT AND DEVELOPMENT, INC                |  | NEW YORK              
|LANDRANCH LIMITED                                   |  | ENGLAND AND WALES     
|LANDWEST, INC                                       |  | NEW YORK              
|LATTICE ENERGY SERVICES LIMITED                     |  | ENGLAND AND WALES     
|LATTICE GROUP EMPLOYEE BENEFIT TRUST LIMITED        |  | ENGLAND AND WALES     
|LATTICE GROUP HOLDINGS LIMITED                      |  | ENGLAND AND WALES     
|LATTICE GROUP INTERNATIONAL HOLDINGS LIMITED        |  | ENGLAND AND WALES     
|LATTICE GROUP PLC                                   |  | ENGLAND AND WALES     
|LATTICE GROUP SERVICES LIMITED                      |  | ENGLAND AND WALES     
|LATTICE GROUP TRUSTEES LIMITED                      |  | ENGLAND AND WALES     
|LATTICE GROUP US HOLDINGS, INC.                     |  | DELAWARE              
|LATTICE INTELLECTUAL PROPERTY LIMITED               |  | ENGLAND AND WALES     
|                                                    |  |                       

---



|LATTICE LIMITED                                              |  | ENGLAND AND WALES
|------------------------------------------------------------ |  | -----------------
|LATTICE OPSCO LIMITED                                        |  | ENGLAND AND WALES
|LATTICE TELECOM FINANCE (NO 1) LIMITED                       |  | ISLE OF MAN      
|LATTICE TELECOMMUNICATIONS ASSET DEVELOPMENT COMPANY LIMITED |  | ENGLAND AND WALES
|LOUGHBOROUGH PARK MANAGEMENT LIMITED                         |  | ENGLAND AND WALES
|MAINSTREAM FORTY-SEVEN LIMITED                               |  | ENGLAND AND WALES
|MASSACHUSETTS ELECTRIC COMPANY                               |  | MASSACHUSETTS    
|MELMAR LIMITED                                               |  | ISLE OF MAN      
|MERCATOR DEVELOPMENTS LIMITED                                |  | UNITED KINGDOM   
|METROWEST REALTY LLC                                         |  | DELAWARE         
|MOREAU PARK, INC                                             |  | NEW YORK         
|NANTUCKET ELECTRIC COMPANY                                   |  | MASSACHUSETTS    
|NATGRID FINANCE HOLDINGS LIMITED                             |  | ENGLAND AND WALES
|NATGRID FINANCE LIMITED                                      |  | ENGLAND AND WALES
|NATGRID HOLDINGS LIMITED                                     |  | ENGLAND AND WALES
|NATGRID INVESTMENTS LIMITED                                  |  | ENGLAND AND WALES
|NATGRID LIMITED                                              |  | ENGLAND AND WALES
|NATIONAL GRID (IOM) UK LTD                                   |  | ENGLAND AND WALES
|NATIONAL GRID (IRELAND) 1 LIMITED                            |  | ENGLAND AND WALES
|NATIONAL GRID (IRELAND) 2 LIMITED                            |  | ENGLAND AND WALES
|NATIONAL GRID (US) HOLDINGS LIMITED                          |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS                               |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS 2                             |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS 3                             |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS 4                             |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS 5                             |  | ENGLAND AND WALES
|NATIONAL GRID (US) INVESTMENTS 6                             |  | ENGLAND AND WALES
|NATIONAL GRID (US) PARTNER 1 LIMITED                         |  | ENGLAND AND WALES
|NATIONAL GRID (US) PARTNER 2 LIMITED                         |  | ENGLAND AND WALES
|NATIONAL GRID ADVANTICA LIMITED                              |  | ENGLAND AND WALES
|NATIONAL GRID AUSTRALIA PTY LIMITED                          |  | CAYMAN ISLANDS   
|NATIONAL GRID BASSLINK LIMITED                               |  | ENGLAND AND WALES
|NATIONAL GRID BRAZIL B.V.                                    |  | NETHERLANDS      
|NATIONAL GRID BRAZIL FINANCE                                 |  | ENGLAND AND WALES
|NATIONAL GRID BRAZIL TRANSMISSION B.V.                       |  | NETHERLANDS      
|NATIONAL GRID CHILE B.V.                                     |  | NETHERLANDS      
|NATIONAL GRID COMMUNICATIONS HOLDINGS, INC.                  |  | MASSACHUSETTS    
|NATIONAL GRID COMMUNICATIONS, INC.                           |  | MASSACHUSETTS    
|NATIONAL GRID COMPANY HOLDINGS LIMITED                       |  | ENGLAND AND WALES
|NATIONAL GRID COMPANY PLC                                    |  | ENGLAND AND WALES
|NATIONAL GRID CONNECTIONS LIMITED                            |  | ENGLAND AND WALES
|NATIONAL GRID DISTRIBUTION LIMITED                           |  | ENGLAND AND WALES
|NATIONAL GRID EIGHT LIMITED                                  |  | ENGLAND AND WALES
|NATIONAL GRID EIGHTEEN LIMITED                               |  | ENGLAND AND WALES
|NATIONAL GRID ELECTRICITY LIMITED                            |  | ENGLAND AND WALES
|NATIONAL GRID ELECTRICITY TRANSMISSION LIMITED               |  | ENGLAND AND WALES
|NATIONAL GRID ELEVEN LIMITED                                 |  | ENGLAND AND WALES
|NATIONAL GRID FIFTEEN LIMITED                                |  | ENGLAND AND WALES
|NATIONAL GRID FINANCE B.V.                                   |  | NETHERLANDS      
|NATIONAL GRID FIVE LIMITED                                   |  | ENGLAND AND WALES
|                                                             |  |                  

---



|NATIONAL GRID FOUR LIMITED                   |  | ENGLAND AND WALES   
|-------------------------------------------- |  | --------------------
|NATIONAL GRID FOURTEEN LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID GAS LIMITED                    |  | ENGLAND AND WALES   
|NATIONAL GRID GENERAL PARTNERSHIP            |  | DELAWARE            
|NATIONAL GRID GOLD LIMITED                   |  | ENGLAND AND WALES   
|NATIONAL GRID GROUP LIMITED                  |  | ENGLAND AND WALES   
|NATIONAL GRID HOLDINGS B.V.                  |  | NETHERLANDS         
|NATIONAL GRID HOLDINGS INC.                  |  | DELAWARE            
|NATIONAL GRID HOLDINGS LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID HOLDINGS ONE PLC               |  | ENGLAND AND WALES   
|NATIONAL GRID HOLLAND LIMITED                |  | ENGLAND AND WALES   
|NATIONAL GRID INDIA B.V.                     |  | NETHERLANDS         
|NATIONAL GRID INDUS B.V.                     |  | ENGLAND AND WALES   
|NATIONAL GRID INTERNATIONAL LIMITED          |  | ENGLAND AND WALES   
|NATIONAL GRID IRELAND THREE                  |  | MALTA               
|NATIONAL GRID JERSEY HOLDINGS FIVE LIMITED   |  | JERSEY              
|NATIONAL GRID JERSEY HOLDINGS THREE LIMITED  |  | JERSEY              
|NATIONAL GRID JERSEY INVESTMENTS LIMITED     |  | ENGLAND             
|NATIONAL GRID JERSEY INVESTMENTS TWO LIMITED |  | ENGLAND AND WALES   
|NATIONAL GRID LNG LIMITED                    |  | ENGLAND AND WALES   
|NATIONAL GRID MANQUEHUE B.V.                 |  | NETHERLANDS         
|NATIONAL GRID MARKET SERVICES LIMITED        |  | ENGLAND AND WALES   
|NATIONAL GRID METERING LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID MIDDLE EAST FZCO               |  | UNITED ARAB EMIRATES
|NATIONAL GRID NETHERLANDS ONE BV             |  | NETHERLANDS         
|NATIONAL GRID NETHERLANDS THREE BV           |  | NETHERLANDS         
|NATIONAL GRID NETHERLANDS TWO BV             |  | NETHERLANDS         
|NATIONAL GRID NINE LIMITED                   |  | ENGLAND AND WALES   
|NATIONAL GRID NINETEEN LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID ONE LIMITED                    |  | ENGLAND AND WALES   
|NATIONAL GRID OVERSEAS LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID OVERSEAS TWO LIMITED           |  | ENGLAND AND WALES   
|NATIONAL GRID PENSIONS LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID POLAND B.V.                    |  | NETHERLANDS         
|NATIONAL GRID PROCUREMENT BV                 |  | NETHERLANDS         
|NATIONAL GRID PROPERTIES LIMITED             |  | ENGLAND AND WALES   
|NATIONAL GRID PROPERTY LIMITED               |  | ENGLAND AND WALES   
|NATIONAL GRID SEVEN LIMITED                  |  | ENGLAND AND WALES   
|NATIONAL GRID SEVENTEEN LIMITED              |  | ENGLAND AND WALES   
|NATIONAL GRID SIX LIMITED                    |  | ENGLAND AND WALES   
|NATIONAL GRID SIXTEEN LIMITED                |  | ENGLAND AND WALES   
|NATIONAL GRID TEN                            |  | ENGLAND AND WALES   
|NATIONAL GRID THREE LIMITED                  |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO EUROPE LIMITED         |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO GROUP LIMITED          |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO HOLDINGS LIMITED       |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO INTERNATIONAL LIMITED  |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO ONE LIMITED            |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO PLC                    |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSCO UK LIMITED             |  | ENGLAND AND WALES   
|NATIONAL GRID TRANSMISSION LIMITED           |  | ENGLAND AND WALES   
|                                             |  |                     

---



|NATIONAL GRID TRANSMISSION SERVICES CORPORATION       |  | MASSACHUSETTS    
|----------------------------------------------------- |  | -----------------
|NATIONAL GRID TWELVE LIMITED                          |  | ENGLAND AND WALES
|NATIONAL GRID TWENTY LIMITED                          |  | ENGLAND AND WALES
|NATIONAL GRID TWENTY ONE LIMITED                      |  | ENGLAND AND WALES
|NATIONAL GRID TWO LIMITED                             |  | ENGLAND AND WALES
|NATIONAL GRID US 6 LLC                                |  | UNITED STATES    
|NATIONAL GRID US LLC                                  |  | DELAWARE         
|NATIONAL GRID USA                                     |  | DELAWARE         
|NATIONAL GRID USA SERVICE COMPANY, INC.               |  | MASSACHUSETTS    
|NATIONAL GRID WIRELESS LIMITED                        |  | ENGLAND AND WALES
|NATIONAL GRID ZAMBIA B.V.                             |  | NETHERLANDS      
|NATIONAL GRID ZAMBIA LIMITED                          |  | ENGLAND AND WALES
|NEES COMMUNICATIONS, INC.                             |  | MASSACHUSETTS    
|NEES ENERGY, INC.                                     |  | MASSACHUSETTS    
|NEES TELECOMMUNICATIONS CORP.                         |  | MASSACHUSETTS    
|NETMAP LIMITED                                        |  | ENGLAND AND WALES
|NETWORK MAPPING LIMITED                               |  | ENGLAND AND WALES
|NEW ENGLAND ELECTRIC TRANSMISSION CORPORATION         |  | NEW HAMPSHIRE    
|NEW ENGLAND ENERGY INCORPORATED                       |  | MASSACHUSETTS    
|NEW ENGLAND HYDRO FINANCE COMPANY, INC.               |  | MASSACHUSETTS    
|NEW ENGLAND HYDRO-TRANSMISSION CORPORATION            |  | NEW HAMPSHIRE    
|NEW ENGLAND HYDRO-TRANSMISSION ELECTRIC COMPANY, INC. |  | MASSACHUSETTS    
|NEW ENGLAND POWER COMPANY                             |  | MASSACHUSETTS    
|NEW ENGLAND WHOLESALE ELECTRIC COMPANY                |  | MASSACHUSETTS    
|NEWHC, INC.                                           |  | MASSACHUSETTS    
|NG AUSTRALIA GP PTY LTD                               |  | AUSTRALIA        
|NG AUSTRALIA LLP                                      |  | AUSTRALIA        
|NG CHICAGO I LLC                                      |  | DELAWARE         
|NG CHICAGO II, LLC                                    |  | DELAWARE         
|NG JERSEY LIMITED                                     |  | JERSEY           
|NG MALTA ONE LIMITED                                  |  | ENGLAND AND WALES
|NG PROCUREMENT HOLDINGS LIMITED                       |  | ENGLAND AND WALES
|NG PROPERTY DEVELOPMENTS LIMITED                      |  | ENGLAND AND WALES
|NGC (GB) LIMITED                                      |  | ENGLAND AND WALES
|NGC DO BRASIL PARTICIPACOES LTDA                      |  | BRAZIL           
|NGC EMPLOYEE SHARES TRUSTEE LIMITED                   |  | ENGLAND AND WALES
|NGC ENERGY LIMITED                                    |  | ENGLAND AND WALES
|NGC INDUS LIMITED                                     |  | ENGLAND AND WALES
|NGC IT LIMITED                                        |  | ENGLAND AND WALES
|NGC LEASING LIMITED                                   |  | ENGLAND AND WALES
|NGC LEISURE LIMITED                                   |  | ENGLAND AND WALES
|NGC TWO LIMITED                                       |  | ENGLAND AND WALES
|NGC ZAMBIA LIMITED                                    |  | ENGLAND AND WALES
|NGG (DELAWARE) LLC                                    |  | DELAWARE         
|NGG FINANCE (NO 1) LIMITED                            |  | ENGLAND AND WALES
|NGG FINANCE PLC                                       |  | ENGLAND AND WALES
|NGG LIMITED                                           |  | ENGLAND AND WALES
|NGG TELECOMS HOLDINGS LIMITED                         |  | ENGLAND AND WALES
|                                                      |  |                  

---



|NGG TELECOMS INVESTMENT LIMITED             |  | ENGLAND AND WALES
|------------------------------------------- |  | -----------------
|NGG TELECOMS LIMITED                        |  | ENGLAND AND WALES
|NGT CONNECTIONS (NO 1) LIMITED              |  | ENGLAND AND WALES
|NGT CONNECTIONS (NO 2) LIMITED              |  | ENGLAND AND WALES
|NGT FIVE LIMITED                            |  | ENGLAND AND WALES
|NGT FOUR LIMITED                            |  | ENGLAND AND WALES
|NGT HOLDING COMPANY (ISLE OF MAN) LIMITED   |  | ISLE OF MAN      
|NGT HOLDINGS LIMITED                        |  | ENGLAND AND WALES
|NGT INSURANCE COMPANY (GUERNSEY) LIMITED    |  | ISLE OF MAN      
|NGT INSURANCE COMPANY (IRELAND) LIMITED     |  | IRELAND          
|NGT INSURANCE COMPANY (ISLE OF MAN) LIMITED |  | ISLE OF MAN      
|NGT INTELLECTUAL PROPERTY LIMITED           |  | ENGLAND AND WALES
|NGT INTERCONNECTORS LIMITED                 |  | ENGLAND AND WALES
|NGT LUXEMBOURG ONE LIMITED                  |  | ENGLAND & WALES  
|NGT LUXEMBOURG TWO LIMITED                  |  | ENGLAND & WALES  
|NGT METERING LIMITED                        |  | ENGLAND AND WALES
|NGT NOMINEES LIMITED                        |  | ENGLAND AND WALES
|NGT ONE LIMITED                             |  | ENGLAND AND WALES
|NGT ONSTREAM LIMITED                        |  | ENGLAND AND WALES
|NGT TELECOM NO.1 LIMITED                    |  | ENGLAND AND WALES
|NGT TELECOM NO.2 LIMITED                    |  | ENGLAND AND WALES
|NGT THREE LIMITED                           |  | UNITED KINGDOM   
|NGT TWO LIMITED                             |  | ENGLAND AND WALES
|NGT UK HOLDINGS LIMITED                     |  | ENGLAND AND WALES
|NGT UK LIMITED                              |  | ENGLAND AND WALES
|NGTM HOLDINGS LIMITED                       |  | UNITED KINGDOM   
|NIAGARA MOHAWK HOLDINGS, INC.               |  | NEW YORK         
|NIAGARA MOHAWK POWER CORPORATION            |  | NEW YORK         
|NM PROPERTIES, INC.                         |  | NEW YORK         
|NM RECEIVABLES CORP. II                     |  | NEW YORK         
|NM RECEIVABLES, LLC                         |  | NEW YORK         
|NM URANIUM, INC.                            |  | TEXAS            
|NT LIMITED                                  |  | ENGLAND AND WALES
|ON STREAM ASSET MANAGEMENT SERVICES LIMITED |  | ENGLAND AND WALES
|ON STREAM DATA MANAGEMENT LIMITED           |  | ENGLAND AND WALES
|ON STREAM DATA PROVISION LIMITED            |  | ENGLAND AND WALES
|ON STREAM METER OPERATIONS LIMITED          |  | ENGLAND AND WALES
|ON STREAM METER READING SERVICES LIMITED    |  | ENGLAND AND WALES
|ON STREAM METERING LIMITED                  |  | ENGLAND AND WALES
|ON STREAM SERVICES LIMITED                  |  | ENGLAND AND WALES
|ON STREAM SOLUTIONS LIMITED                 |  | ENGLAND AND WALES
|ON STREAM UTILITIES LIMITED                 |  | ENGLAND AND WALES
|ON STREAM.COM LIMITED                       |  | ENGLAND AND WALES
|ONSTREAM METERING SERVICES LIMITED          |  | ENGLAND AND WALES
|OPINAC ENERGY CORPORATION                   |  | CANADA           
|OPINAC NORTH AMERICA, INC.                  |  | DELAWARE         
|OPROPCO, INC                                |  | NEW YORK         
|PORT GREENWICH LIMITED                      |  | ENGLAND AND WALES
|POWERCOM LIMITED                            |  | ENGLAND AND WALES
|RISX ENVIRONMENTAL MANAGEMENT LIMITED       |  | SCOTLAND         
|RISX LIMITED                                |  | SCOTLAND         
|                                            |  |                  

---



|RIVERVIEW, INC                                        |  | NEW YORK         
|----------------------------------------------------- |  | -----------------
|RT MASTS LIMITED                                      |  | ENGLAND AND WALES
|SALMON SHORES, INC                                    |  | NEW YORK         
|SECONDSITE (SOUTHALL) GENERAL PARTNER LIMITED         |  | UNITED KINGDOM   
|SECONDSITE (SOUTHALL) LP LIMITED                      |  | UNITED KINGDOM   
|SECONDSITE ESTATES LIMITED                            |  | ENGLAND AND WALES
|SECONDSITE HOLDINGS LIMITED                           |  | ENGLAND AND WALES
|SECONDSITE LAND DEVELOPMENTS LIMITED                  |  | ENGLAND AND WALES
|SECONDSITE LAND INVESTMENTS LIMITED                   |  | ENGLAND AND WALES
|SECONDSITE PORTFOLIO SOLUTIONS LIMITED                |  | ENGLAND AND WALES
|SECONDSITE PROPERTY (NORTHAMPTON) LIMITED             |  | UNITED KINGDOM   
|SECONDSITE PROPERTY HOLDINGS LIMITED                  |  | ENGLAND AND WALES
|SECONDSITE PROPERTY LIMITED                           |  | ENGLAND AND WALES
|SECONDSITE PROPERTY NOMINEES (NO 1) LIMITED           |  | ENGLAND AND WALES
|SECONDSITE PROPERTY NOMINEES (NO 2) LIMITED           |  | ENGLAND AND WALES
|SECONDSITE PROPERTY PORTFOLIO LIMITED                 |  | ENGLAND AND WALES
|SECONDSITE REGENERATION LIMITED                       |  | ENGLAND AND WALES
|SSE TRANSCO LIMITED                                   |  | ENGLAND AND WALES
|SST GMBH                                              |  | GERMANY          
|SST TOWERS COMMUNICATIONS SAS                         |  | FRANCE           
|STARGAS NOMINEES LIMITED                              |  | ENGLAND AND WALES
|STC INTERNATIONAL HOLDINGS LIMITED                    |  | ENGLAND AND WALES
|STONER ASSOCIATES EUROPE LIMITED                      |  | ENGLAND AND WALES
|SUPERGRID ENERGY TRANSMISSION LIMITED                 |  | ENGLAND AND WALES
|SUPERGRID LIMITED                                     |  | ENGLAND AND WALES
|TELDATA INTERNATIONAL LIMITED                         |  | ENGLAND AND WALES
|TELDATA SERVICES LIMITED                              |  | ENGLAND AND WALES
|TELDATA SOLUTIONS LIMITED                             |  | ENGLAND AND WALES
|TELECOM ELECTRIC LIMITED                              |  | ENGLAND AND WALES
|TELECOM INTERNATIONAL HOLDINGS LIMITED                |  | ENGLAND AND WALES
|TELINK LIMITED                                        |  | ENGLAND AND WALES
|TERRACOM DESIGN & DEVELOPMENT LIMITED                 |  | ENGLAND AND WALES
|TERRACOM ESTATES LIMITED                              |  | ENGLAND AND WALES
|THE ELECTRICITY TRANSMISSION COMPANY LIMITED          |  | ENGLAND AND WALES
|THE NARRAGANSETT ELECTRIC COMPANY                     |  | RHODE ISLAND     
|THE NATIONAL GRID GROUP QUEST TRUSTEE COMPANY LIMITED |  | ENGLAND AND WALES
|THE NATIONAL GRID INVESTMENTS COMPANY                 |  | ENGLAND AND WALES
|TOREN CV                                              |  | NETHERLANDS      
|TRANSCO (EMPLOYERS) LTD                               |  | ENGLAND AND WALES
|TRANSCO ASSET MAINTENANCE (SCOTLAND) LIMITED          |  | ENGLAND AND WALES
|TRANSCO ASSET MAINTENANCE (WALES) LIMITED             |  | ENGLAND AND WALES
|TRANSCO ASSET MAINTENANCE LIMITED                     |  | ENGLAND AND WALES
|TRANSCO ASSET MANAGEMENT (SCOTLAND) LIMITED           |  | ENGLAND AND WALES
|TRANSCO ASSET MANAGEMENT (WALES) LIMITED              |  | ENGLAND AND WALES
|TRANSCO ASSET MANAGEMENT LIMITED                      |  | ENGLAND AND WALES
|TRANSCO CONNECTIONS (SCOTLAND) LIMITED                |  | ENGLAND AND WALES
|TRANSCO CONNECTIONS (WALES) LIMITED                   |  | ENGLAND AND WALES
|TRANSCO CONNECTIONS LIMITED                           |  | ENGLAND AND WALES
|TRANSCO EMERGENCY SERVICES (SCOTLAND) LIMITED         |  | ENGLAND AND WALES
|TRANSCO EMERGENCY SERVICES (WALES) LIMITED            |  | ENGLAND AND WALES
|                                                      |  |                  

---



|TRANSCO EMERGENCY SERVICES LIMITED                           |  | ENGLAND AND WALES
|------------------------------------------------------------ |  | -----------------
|TRANSCO HOLDINGS (EMPLOYERS) LTD                             |  | ENGLAND AND WALES
|TRANSCO HOLDINGS PLC                                         |  | ENGLAND AND WALES
|TRANSCO LNG STORAGE LIMITED                                  |  | ENGLAND AND WALES
|TRANSCO METERING SERVICES (SCOTLAND) LIMITED                 |  | ENGLAND AND WALES
|TRANSCO METERING SERVICES LIMITED                            |  | ENGLAND AND WALES
|TRANSCO PIPELINE CONSTRUCTORS (SCOTLAND) LIMITED             |  | ENGLAND AND WALES
|TRANSCO PIPELINE CONSTRUCTORS (WALES) LIMITED                |  | ENGLAND AND WALES
|TRANSCO PIPELINE CONSTRUCTORS LIMITED                        |  | ENGLAND AND WALES
|TRANSCO PIPELINES (SCOTLAND) LIMITED                         |  | ENGLAND AND WALES
|TRANSCO PIPELINES (WALES) LIMITED                            |  | ENGLAND AND WALES
|TRANSCO PIPELINES LIMITED                                    |  | ENGLAND AND WALES
|TRANSCO PLC                                                  |  | ENGLAND AND WALES
|TRANSCO TELECOMMUNICATIONS ASSET DEVELOPMENT COMPANY LIMITED |  | ENGLAND AND WALES
|TRANSCO TRANSPORTATION COMPANY LIMITED                       |  | ENGLAND AND WALES
|TRANSGRID LIMITED                                            |  | ENGLAND AND WALES
|TRISCAPE PLANNING LIMITED                                    |  | ENGLAND AND WALES
|UPPER HUDSON DEVELOPMENT INC                                 |  | NEW YORK         
|UTILITY METERING SERVICES LIMITED                            |  | ENGLAND AND WALES
|VESAS LIMITED                                                |  | ENGLAND AND WALES
|WAYFINDER GROUP, INC.                                        |  | MASSACHUSETTS    
|XOSERVE (UK) LIMITED                                         |  | ENGLAND AND WALES
|XOSERVE HOLDINGS LIMITED                                     |  | ENGLAND AND WALES
|XOSERVE LIMITED                                              |  | UNITED KINGDOM   

---



QuickLinks