The Mayor of London has been accused of “failing” to tackle the capital’s housing “emergency” as new figures showed developers only started building 347 affordable homes in the first three months of this year.

The Greater London Authority (GLA) and the Ministry of Housing, Communities and Local Government have agreed that London’s target for the Affordable Homes Programme should be a minimum of 17,800 starts by March 2026.

This represents a 22 per cent cut on the previous aim of 23,900 starts between 2021 and 2026.

However, work has only started on 5,535 affordable homes, according to the annual Affordable Housing Monitor, meaning Sir Sadiq Khan is around 12,300 short of his target with nine months remaining.

Earlier today the Mayor’s Office said “national funding, high interest rates, spiralling building costs, delays from bodies like the Building Safety Regulator and the lasting impact of Brexit” had all slowed down building.

Enfield was the most prolific of any London borough, with 181 starts on affordable homes reported between April and June this year.

They were followed by Newham, Southwark, Camden and Sutton – with the remaining 27 boroughs failing to make 10 or more starts.

Chair of the London Assembly Housing Committee, Zoë Garbett, told the London Democracy Reporting Service: “We are far beyond a housing crisis – London has a housing emergency. The gap between what’s being delivered and what’s desperately needed is incredibly concerning.

“With the affordable housing currently being delivered each year so far below the Greater London Authority’s own estimates of what’s needed, it is vital the Mayor uses every tool at his disposal to start turning this around.”

Lib Dem Group Leader on the London Assembly Hina Bokhari told the London Democracy Reporting Service: “These figures are yet more proof that Sadiq Khan has no idea how to even begin to tackle London’s housing crisis. He’s consistently broken all his targets for affordable homes and Londoners are paying the price.

“After nearly a decade in City Hall – and now with a Labour Government at his back – the Mayor has finally run out of any possible excuse for such a terrible track record.”

In May, the GLA said it still intended to deliver between 18,800 and 19,000 new homes by next March.

Lord Bailey, the City Hall Conservatives Housing spokesman, told the Local Democracy Reporting Service: “London’s housing crisis becomes more severe with every passing day, putting an increasing burden on Londoners and London councils with rising rents and mortgages.

“Struggling Londoners need the Government to succeed in tackling this issue but Khan is clearly failing, and we all pay the price.

“How will he ever meet his own targets, let alone the targets his own Government has set him? He’s the weakest link in this chain.”

Conservative Party chairman Kevin Hollinrake added: “At this rate, London faces the worst year in a decade for new affordable homes. Londoners deserve action, not excuses.”

A spokesperson for the Mayor of London told the Local Democracy Reporting Service: “The horrendous legacy of the last government – including a lack of national funding, high interest rates, spiralling building costs, delays from bodies like the Building Safety Regulator and the lasting impact of Brexit – has made it harder and more expensive to build homes, with Londoners suffering the consequences.

 “Sadiq has made tackling this crisis a priority since he took office, and despite these challenges the highest number of affordable homes for social rent in a decade were completed last year. We will continue working to deliver the social and affordable homes that Londoners desperately need, including through a new £11.7 billion affordable housing fund from central Government – the biggest and longest-term settlement in City Hall’s history.

 “The Mayor is taking the hard decisions to improve housing supply of all tenures. He is actively exploring releasing parts of London’s green belt for development, and is working closely with the Government to resolve issues like delays from the Building Safety Regulator. We continue to work with Ministers to turn this crisis around and build a better, fairer London for everyone.”