The number of affordable homes built in Epsom and Ewell is falling due to challenging changes in planning law introduced by the Government.

In the last financial year, 2014 to 2015, only 58 affordable properties were built - the lowest number since 2010 to 2011.

In a document published ahead of a meeting of Epsom Council’s licensing and planning policy committee earlier this month, it said: "In the long-term it is likely that the number of affordable units being delivered on a yearly basis will remain lower than previously anticipated."

The council said many factors contributed to this - including the use of "viability appraisals" by developers to negotiate down the scale of affordable housing to be provided in a new build, and a change in the threshold of a development which would require affordable housing to be provided - from a development of five properties to 10.

Epsom Council requires 35 per cent of new developments to include a quota of affordable housing. But developers have used viability assessments on a number of occasions in recent years, resulting in fewer affordable homes being provided.

The borough has largely relied upon the closure of the former mental hospitals to meet its housing targets in the past few years. But big upcoming projects include Nescot, which is predicted to bring in 36 affordable homes, Shaftsbury House, 45, Hollymoor Lane, 31, and The Lintons Centre, 34.

Residents’ Association (RA) Councillor Graham Dudley, chairman of the licensing and planning policy committee, said: "The recent changes in Government policy hasn’t helped. It has helped the number of starts but not the corresponding increase in affordable housing."

He said the viability issue is "something over which we don’t have very much control".

Coun Dudley said he hopes the borough’s greenbelt - which comprises 42 per cent of it - will be preserved and the RA are "very determined" to keep it "as far as they possibly can".

On the national change in the threshold required for affordable housing, a Council spokesman said: "The council, along with many other authorities nationally, challenged this proposal at the consultations stage due to the negative impact that it would have on affordable housing supply in the borough.

"The Government took the decision to implement the provisions in order to reduce the planning costs for small scale and self-build development."

He said developers’ viability assessments were scrutinised by an independent expert appointed by the council.

The spokesman added: "In the case where a reduced level of affordable housing is agreed due to legitimate viability constraints, the council will often require that a review of the development must take place later in the process to establish if the position has changed and more affordable housing can be provided."

The borough beat its target of seeing 181 homes built by 12 units in the last year, but the amount was still lower than the year before, with two large developments taking longer than expected - Shaftsbury House and the Lintons Centre, according to the council.

The council has set itself a target of seeing 3,620 homes built by 2026 on 18 new sites and estimates it will beat that by 562 units.

OTHER HOUSING FACTS FROM 2014 to 2015

Average house prices increased by 13 per cent

Epsom and Ewell's population of 77,100 increased by 10,041 since 2001

The number of homes has increased by 2,961 to 30,947 since 2001

Average house price 2014 according to Rightmove: Epsom £424,928 (13 per cent increase), Ewell £424,928 (10 percent increase) £440,738 in Stoneleigh (9% increase), £441,145 in Epsom Downs (24% increase)