Sadiq Khan’s team has written to a housing association about the selling-off of “key worker” homes on the Victoria Park Estate.

Peabody’s decision to auction three of the homes it bought from the Crown Estate in 2011 sparked a huge backlash from the community and Hackney Council late last year.

The properties had housed public servants such as police officers and nurses, and when the sale went through in 2011 the Victoria Park Community Residents’ Association (VPCRA) – which had campaigned against the deal – secured legal provisions.

Now they say Peabody has breached those conditions by selling off too many, a claim Peabody denies. The VPCRA now wants to stop the planned auctions of the four-bed terrace in Gore Road and two other properties in Old Ford Road and Robinson Road on the other side of the park in Tower Hamlets.

Member Nik Wood said: “In 2010 we were all unhappy about the crown privatising us but a buyer who presented itself as a philanthropic, charitable landlord seemed an acceptable outcome.

“Peabody, like the housing association sector generally, has moved away from this model towards being a hard-nosed property developer. These sales are just one example.”

London Assembly member Sian Berry also took on the matter, asking the mayor of London if he was concerned about the sales.

In response, Mr Khan said his team had contacted Peabody about the sales. He added: “I believe sales of affordable housing should be avoided wherever possible. Where they take place, they should be kept to a minimum, and any proceeds should be reinvested in new affordable homes.”

Ms Berry’s colleague Samir Jeraj, a Green member in Hackney, said: “The residents I’ve spoken to in Victoria Park are worried about the future of their community because of these sell-offs. Peabody needs to work with and listen to residents.”

In October Hackney mayor Phil Glanville and Tower Hamlets mayor John Biggs wrote to Peabody asking why the homes were being sold.

The mayors said: “We know there was a campaign to ensure they were not sold to a private landlord, and assurances were sought that the homes would remain affordable and available to key workers.”

The letter added: “Can you offer assurances that key worker housing is being protected?”

Peabody maintain they only sell homes when they are not suitable to be rented out.

A spokesperson said: “We are not in breach of our agreement with the Crown Estate and talk regularly with officers in the boroughs and the GLA on our position.

“We would reiterate that the funds raised from the small number of sales allow us to invest in maintenance and building more homes.”