Built in the 1930s, it is still the largest single block of private rented flats in London and one of the biggest in the country. The block comprises 1,058 flats, a hotel, shops, a Gary Rhodes restaurant and brasserie, a health club, tennis courts and a swimming pool. Current residents include former leader of the Conservative Party William Hague and his wife Ffion. Now Westbrook--former owner of Skibo Castle in Scotland, the venue of Madonna's wedding to Guy Ritchie--has won a bidding war for the block.

This is the second time in as many years that head leaseholder Westminster Council has sought to dispose of the property. But previous attempts to sell it have floundered because of existing agreements with tenants. Dolphin Square has long offered some of London's lowest rents to its residents, some of whom pay less than euro 102 ($125.5) a week in rent, less than half the average for the capital. The rent includes access to a swimming pool, landscaped gardens, squash courts and other privileges.

The freehold of the land is owned by Friends Provident but Westminster's lease runs until 2034. With vacant possession, the block would be worth euro 364 million ($448 million). The fact that Westbrook is paying a quarter of that reflects in part the complex arrangements with existing tenants.

Now Derek Barnden, Westminster council's director of technical services, has confirmed that an agreement had finally been reached between the council and the tenants. Existing tenants will be allowed to retain their existing rents and other conditions regardless of who buys the estate. They will have an option of selling their leases and either moving out or renting their flats at market rent. Another option will be the chance to buy their freeholds at a large discount.