**Exhibit 8.1**

**Subsidiaries**

| **Name**                                                                    | **Jurisdiction of   Incorporation or   Organization** |
|-----------------------------------------------------------------------------|-------------------------------------------------------|
|                                                                        |                                                  |
| ADVANTICA CORPORATE VENTURES LIMITED                                        | England and Wales                                     |
| ADVANTICA, INC.                                                             | Delaware                                              |
| ADVANTICA LIMITED                                                           | England and Wales                                     |
| ADVANTICA PTY LIMITED                                                       | Australia                                             |
| AEMC, L.L.C.                                                                | Delaware                                              |
| AERIAL GROUP LIMITED                                                        | England and Wales                                     |
| AERIAL UK LIMITED                                                           | England and Wales                                     |
| AGL SYSTEMS INTERNATIONAL LIMITED                                           | England and Wales                                     |
| ARBUCKLE ACRES, INC                                                         | New York                                              |
| ATLANTIC WESTERN CONSULTING, INC.                                           | Massachusetts                                         |
| BASSLINK PTY LIMITED                                                        | Australia                                             |
| 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                                           |
| BRITNED DEVELOPMENT LIMITED                                                 | England and Wales                                     |
| C4GAS SA                                                                    | Belgium                                               |
| CEL POLSKA SP ZOO                                                           | Poland                                                |
| CITELEC S.A.                                                                | Argentina                                             |
| COGSYS LIMITED                                                              | England and Wales                                     |
| COPPERBELT ENERGY CORPORATION PLC                                           | Zambia                                                |
| EASTLANDS (BENEFITS ADMINISTRATION) LIMITED                                 | England and Wales                                     |
| ELEXON LIMITED                                                              | England and Wales                                     |
| ENERGIS POLSKA SP. Z O.O.                                                   | Poland                                                |
| EUA BIOTEN, INC.                                                            | Massachusetts                                         |
| EUA ENERGY INVESTMENT CORPORATION                                           | Massachusetts                                         |
| FIRSTPOINT ENERGY CORPORATION                                               | Delaware                                              |
| FULCRUM CONNECTIONS LIMITED                                                 | England and Wales                                     |
| GRAIN LNG LIMITED                                                           | England and Wales                                     |
| GRANITE STATE ELECTRIC COMPANY                                              | New Hampshire                                         |
| GRIDAMERICA HOLDINGS INC.                                                   | Delaware                                              |
| GRIDAMERICA LLC                                                             | Delaware                                              |
| GRIDCOM (UK) LIMITED                                                        | England and Wales                                     |
| GRIDCOM AERIAL SITES PLC                                                    | England and Wales                                     |
| GRIDCOM LIMITED                                                             | England and Wales                                     |
| HOLDCO PARTICIPACOES LTDA                                                   | Brazil                                                |
| HUDSON POINTE, INC.                                                         | New York                                              |
| INTELIG TELECOMUNICACOES LTDA                                               | Brazil                                                |
| INTEROTEX LIMITED                                                           | England and Wales                                     |
| INVERSIONES ABC LIMITADA                                                    | Chile                                                 |
| JOINT RADIO COMPANY LIMITED                                                 | England and Wales                                     |
| JVCO PARTICIPACOES LTDA                                                     | Brazil                                                |
| KITECHNOLOGY HOLDINGS N.V.                                                  | Netherlands                                           |
| LAND MANAGEMENT AND DEVELOPMENT, INC.                                       | New York                                              |
| LANDWEST, INC.                                                              | New York                                              |
| LATTICE ENERGY SERVICES 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 TRUSTEES LIMITED                                              | England and Wales                                     |
| LATTICE GROUP US HOLDINGS, INC.                                             | Delaware                                              |
| LATTICE INTELLECTUAL PROPERTY LIMITED                                       | England and Wales                                     |
| LATTICE TELECOM FINANCE (NO 1) LIMITED                                      | Isle of Man                                           |
| MASSACHUSETTS ELECTRIC COMPANY                                              | Massachusetts                                         |
| 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 INVESTMENTS LIMITED                                                 | England and Wales                                     |
| NATIONAL GRID (IOM) UK LTD                                                  | Isle of Man                                           |
| NATIONAL GRID (IRELAND) 1 LIMITED                                           | Ireland                                               |
| NATIONAL GRID (IRELAND) 2 LIMITED                                           | Ireland                                               |
| 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) PARTNER 1 LIMITED                                        | England and Wales                                     |
| NATIONAL GRID (US) PARTNER 2 LIMITED                                        | England and Wales                                     |
| NATIONAL GRID AUSTRALIA PTY LIMITED                                         | Cayman Islands                                        |
| NATIONAL GRID BRAZIL B.V.                                                   | Netherlands                                           |
| NATIONAL GRID BRAZIL FINANCE                                                | England and Wales                                     |
| NATIONAL GRID CHILE B.V.                                                    | Netherlands                                           |
| NATIONAL GRID COMMUNICATIONS HOLDINGS, INC.                                 | Massachusetts                                         |
| NATIONAL GRID COMMUNICATIONS, INC.                                          | Massachusetts                                         |
| NATIONAL GRID COMPANY PLC                                                   | England and Wales                                     |
| NATIONAL GRID EIGHT LIMITED                                                 | England and Wales                                     |
| NATIONAL GRID EIGHTEEN 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 GENERAL PARTNERSHIP                                           | Delaware                                              |
| NATIONAL GRID GOLD 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 INDUS B.V.                                                    | Netherlands                                           |
| NATIONAL GRID INTERNATIONAL LIMITED                                         | England and Wales                                     |
| NATIONAL GRID IRELAND THREE                                                 | Ireland                                               |
| NATIONAL GRID JERSEY HOLDINGS FIVE LIMITED                                  | Jersey                                                |
| NATIONAL GRID JERSEY HOLDINGS THREE LIMITED                                 | Jersey                                                |
| NATIONAL GRID MANQUEHUE B.V.                                                | Netherlands                                           |
| 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 POLAND B.V.                                                   | Netherlands                                           |
| NATIONAL GRID PROCUREMENT BV                                                | Netherlands                                           |
| NATIONAL GRID PROPERTIES 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 PLC                                                   | 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 4 LP   (NB: FIRST INCORPORATED AS NATIONAL GRID US 4 INC.) | Delaware                                              |
| NATIONAL GRID US LLC                                                        | Delaware                                              |
| NATIONAL GRID USA                                                           | Delaware                                              |
| NATIONAL GRID USA SERVICE COMPANY, INC.                                     | Massachusetts                                         |
| 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                                         |
| 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 JERSEY LIMITED                                                           | Jersey                                                |
| NG MALTA ONE LIMITED                                                        | Gibraltar                                             |
| NG MALTA TWO LIMITED                                                        | Malta                                                 |
| NG PROCUREMENT HOLDINGS LIMITED                                             | England and Wales                                     |
| NG PROPERTY DEVELOPMENTS LIMITED                                            | England and Wales                                     |
| NGC DO BRASIL PARTICIPACOES LTDA                                            | Brazil                                                |
| NGC LEASING 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 TELECOMS HOLDINGS LIMITED                                               | England and Wales                                     |
| NGG TELECOMS INVESTMENT LIMITED                                             | England and Wales                                     |
| NGG TELECOMS 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 NOMINEES LIMITED                                                        | England and Wales                                     |
| NGT TELECOM NO.1 LIMITED                                                    | England and Wales                                     |
| NGT UK LIMITED                                                              | England and Wales                                     |
| 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                                              |
| OPINAC ENERGY CORPORATION                                                   | Ontario                                               |
| OPINAC NORTH AMERICA, INC.                                                  | Delaware                                              |
| OPROPCO, INC.                                                               | New York                                              |
| PORT GREENWICH LIMITED                                                      | England and Wales                                     |
| RISX LIMITED                                                                | Scotland                                              |
| RIVERVIEW, INC.                                                             | New York                                              |
| RT MASTS LIMITED                                                            | England and Wales                                     |
| SALMON SHORES, INC.                                                         | New York                                              |
| SECONDSITE LAND INVESTMENTS LIMITED                                         | England and Wales                                     |
| SECONDSITE PROPERTY HOLDINGS LIMITED                                        | England and Wales                                     |
| SECONDSITE PROPERTY PORTFOLIO LIMITED                                       | England and Wales                                     |
| SST TOWERS COMMUNICATIONS SAS                                               | France                                                |
| STC INTERNATIONAL HOLDINGS LIMITED                                          | England and Wales                                     |
| STONER ASSOCIATES EUROPE LIMITED                                            | England and Wales                                     |
| TELDATA INTERNATIONAL LIMITED                                               | England and Wales                                     |
| TELECOM INTERNATIONAL HOLDINGS LIMITED                                      | England and Wales                                     |
| TELINK LIMITED                                                              | England and Wales                                     |
| THE ELECTRICITY TRANSMISSION COMPANY LIMITED                                | England and Wales                                     |
| THE NARRAGANSETT ELECTRIC COMPANY                                           | Rhode Island                                          |
| THE NATIONAL GRID INVESTMENTS COMPANY                                       | England and Wales                                     |
| TOREN CV                                                                    | Netherlands                                           |
| TRANSBA S.A.                                                                | Argentina                                             |
| TRANSCO HOLDINGS PLC                                                        | England and Wales                                     |
| TRANSCO METERING SERVICES LIMITED                                           | England and Wales                                     |
| TRANSCO PLC                                                                 | England and Wales                                     |
| TRANSENER S.A.                                                              | Argentina                                             |
| UPPER HUDSON DEVELOPMENT INC.                                               | New York                                              |
| URBAND LIMITED                                                              | England and Wales                                     |
| UTILITY METERING SERVICES LIMITED D/B/A ONSTREAM                            | England and Wales                                     |
| VIAVERA GMBH                                                                | Germany                                               |
| WAYFINDER GROUP, INC.                                                       | Massachusetts                                         |

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