Tens of thousands of young Britons will be offered the chance to buy their first home with a hefty discount by Prime Minister David Cameron, a scheme he hopes will boost his re-election chances for May next year.

With less than five months to go before what is shaping up to be an unusually close election, Cameron and his Conservatives are keen to show voters that the steady economic recovery they have presided over can, if sustained, lift living standards.

"Under this scheme, first-time buyers will be offered the chance of a 20% discount, unlocking home ownership for a generation," Cameron will say, according to advance extracts of his speech released by his office.

"This is all part of our long-term economic plan to secure a better future for Britain, making sure we are backing those who work hard and get on in life."

Under the Starter Home initiative, first-time buyers below the age of 40 will be able to get a minimum 20 percent discount on 100,000 new homes to be built on under-used or unviable brownfield land.

Planning costs and levies will be waived in return for a promise from housebuilders of such discounts. Aspiring buyers will be asked to register their interest from January, six months earlier than originally planned.