Utilize the input text as a context reference, choose the right relationship between Ashtead Group and London from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

452.30p +4.22% St James's Place (STJ) 952.00p +3.82% TUI AG Reg Shs (DI (KSE: 003160.KS - news ) ) (TUI (LSE: TUI.L - news ) ) 1,077.00p +3.66% Schroders (SDR) 3,104.00p +3.47% Aberdeen Asset Management (Other OTC: ABDNF - news ) (ADN) 403.60p +3.43% London Stock Exchange Group (LSE) 2,546.00p +3.41% Marks & Spencer Group (MKS) 538.00p +3.36% Sports Direct International (Other OTC: SDIPF - news ) (SPD) 730.00p +3.33% International Consolidated Airlines Group SA (CDI) (IAG) 531.00p +3.21% InterContinental Hotels Group (IHG) 2,686.00p +3.07% FTSE 100 - Fallers ARM Holdings (LSE: ARM.L - news ) (ARM) 1,015.00p -2.87% Weir Group (WEIR) 1,596.00p -1.18% Randgold Resources Ltd. (RRS) 4,152.00p -0.72% Ashtead Group (LSE: AHT.L - news ) (AHT) 1,050.00p -0.28% FTSE 250 - Risers Fidelity China Special Situations (LSE: FCSS.L - news ) (FCSS) 141.50p +9.27% Brewin Dolphin Holdings (BRW) 308.60p +6.34% Dignity (DTY) 2,306.00p +5.78% Rank Group (RNK) 235.70p +4.76% Auto Trader Group (AUTO) 315.90p +4.19% Zoopla Property Group (WI) (ZPLA) 238.80p +3.83% Hellermanntyton Group (LSE: HTY.L - news ) (HTY) 343.40p +3.81% Shawbrook Group (LSE: SHAW.L - news ) (SHAW) 349.00p +3.78% ICAP (IAP) 520.50p +3.69% Telecom Plus (LSE: TEP.L - news ) (TEP) 1,010.00p +3.64% FTSE 250 - Fallers Lonmin (LMI) 81.45p -12.33% Renishaw (RSW) 2,089.00p -3.95% Mitchells & Butlers (LSE: MAB.L - news ) (MAB) 429.70p -2.47% Drax Group (LSE: DRX.L - news ) (DRX) 267.00p -2.31% Centamin (DI) (CEY) 59.85p -1.89% esure Group (ESUR) 260.00p -1.85% Nostrum Oil & Gas (LSE: NOG.L - news ) (NOG) 593.00p -1.33% IP Group (LSE: IPO.L - news ) (IPO) 198.40p -1.29% Rotork (Frankfurt: RO41.F - news ) (ROR) 222.30p -1.20% Amec Foster Wheeler (Other OTC: AMCBF - news ) (AMFW) 799.50p -1.17%

Answer: headquarters_location