The number of homes missing minimum national standards in Tower Hamlets has rocketed in the last two years, new figures show.

More than 8,250 council or housing association homes in the borough did not meet the decent homes threshold under the Housing Health and Safety Rating System in 2011-12 – up more than 1,700 from the 2010-11 figures.

The statistics have been released after Tower Hamlets council slashed spending on the scheme, with �3,500 less being spent on each property than in 2010. Tower Hamlets council puts the reduced spending down to improved efficiency and better value through bulk purchases.

Labour councillors said the figures damaged the credibility of Mayor of Tower Hamlets Lutfur Rahman after he made the decent homes programme a cornerstone of his election campaign.

Labour’s spokesman for housing councillor Sirajul Islam said: “The mayor needs to find out what has gone wrong and fix it before more families are forced to live in substandard houses.”

The decent homes programme was rolled out across the UK in 2010. Housing charity Shelter defines a decent home as one which is in a reasonable state of repair, with modern facilities and good insulation and heating.

A council spokesperson said: “The explanation into the increase is due to many building elements reaching the end of their useful life based on the age of the council stock.”

The council also insisted that Mayor Rahman’s 2010 pledge to halve the number of homes falling below this threshold would be met comfortably by 2014/15, promising the figure would drop to just 1,359.