The UK’S largest affordable housing charity is to be set up in central London with £100m made from a property deal

The charity is to be established in Westminster next month using money invested by Westminster council in the Dolphin Square Trust, which owns properties in Pimlico. Residents of the properties, which are usually rented at peppercorn rates, include MPs.

The council gave Dolphin Square Trust £4.6m in 1964 to help it out of financial difficulty. In return it got a leasehold interest in the homes.

The trust and the council are now on the verge of selling their interests to American bank Westbrooks. The trust will plough the £100m it is set to make into the charity, called Dolphin Square Charitable Trust. The council will use its £60m proceeds to upgrade buildings including schools and social services facilities.

Rosemary Westbrook, the council’s head of housing, said the trust would work with housing associations and other organisations to provide homes in the borough.

She said: “The new trust doesn’t provide housing directly itself. It will fund existing housing providers. It’s hard to say how many homes that will produce but it could be 500 to 1000 homes. It will look at schemes that need less subsidy and some with 100% funding.”

The council originally gave money to Dolphin Square Trust as assistance rather than an investment, but the decision had proved shrewd, she said. “The value of land has risen so much in the city so it was a pretty foresightful.”

The charity would fund affordable housing schemes built in the borough but could also fund key-worker schemes elsewhere for people employed in Westminster.

The charity advertised for board members, including housing associations, this week.