Southwark's Labour administration has admitted that it won't meet its commitment to build 1,500 new council homes by 2018, with just 400 to be completed by the end of that year.
Back in 2012 Southwark Council's leader Peter John announced ambitious plans to build 1,000 new council homes across the borough by 2020.
The Southwark Labour manifesto at the 2014 local elections promised 11,000 new council homes but didn't put a timescale on implementing the pledge.
After the election the council published a list of 'fairer future promises' with a specific commitment to build the first 1,500 of the 21,000 homes by 2018, with the rest to follow by 2043.
Now the council has been forced to concede that by the end of 2018 it will have completed fewer than 27 per cent of the promised 1,500 homes.
Cllr Mark Williams, cabinet member for regeneration and new homes, admitted at Tuesday's cabinet meeting: "... we will not be meeting that target – but that is not for lack of work and effort on behalf of the officers.
"From a standing start, this represents a fantastic amount of work.
"Nearly 300 new council homes are already completed with residents already moved in.
"We have a further 263 either on site or that have planning permission.
"By the end of 2018 we would have completed 400 new council homes.
"In total there will be 1,600 – including that 400 – either complete, on site, or with planning permission, with contracts signed and with spades literally about to go into the ground...
"We've learned an awful lot along the process, particularly around consultation with local residents.
"In some cases that has delayed the delivery of new homes, but we've felt ... sometimes it is better to go a little bit slower, consult with residents adequately and correctly, get as much public support as you can before moving forward with the design of these new homes."
Cllr Adele Morris, opposition spokeswoman on housing, said: "Southwark Liberal Democrats are deeply concerned by the lack of progress in building new council homes for Southwark residents.
"The Labour administration pledged to build 1,500 new council homes by 2018 but today they publicly admitted this would not be possible with less than a third set to be completed.
"This news will do little to appease the growing number of vulnerable local residents who are currently on the waiting list for new homes."