A 22-storey building straddling the Hackney and Islington border could provide six floors of office space and 100 private-rented flats – but no on-site “affordable” housing.

The City Road development, designed by architects AHMM, is set to take the place of a car park on the site of the old St Luke’s Workhouse and St Matthew’s Hospital.

Initially, unnamed developers said the huge cost of the scheme meant they couldn’t afford to make even one of the homes affordable, despite policy requiring 50 per cent of them to be just that.

Greater London Authority (GLA) officers questioned the assessment, saying some of the assumptions the developers had made about the costs were “difficult to understand”, and ordered Hackney to consult independently.

A £6.25million surplus was then found from somewhere, meaning 56 affordable properties will now be included in the project, but not in the same development.

Before approving the scheme at a town hall meeting last week, Hackney planners decided having 56 affordable homes elsewhere in the borough was better than having 21 affordable flats on site. GLA policy says a scheme’s affordable housing should only be built off-site under exceptional circumstances.

But chair of the Hackney Society planning group Nick Perry, who was at the meeting, said there was nothing exceptional about the plans, adding the decision did nothing to stop exclusivity.

He said: “What about mixed communities? Ghettoising affordable housing merely inflates house prices further because the private developments become exclusive.

“There could have been 20 to 25 genuinely affordable one-bed flats in the heart of Shoreditch. But Hackney chose 56 flats in a distant land.”

Nick also took issue with Hackney officers saying the scheme provided a lot of affordable homes, when at 36 per cent and not on site it falls some way below the 50pc on-site policy.

The scheme will now be referred to GLA planners before final approval.