Persimmon, which builds homes across the country apart from central London, said its new financial year had started well, with private sale rates per site up 25 percent in the first 15 weeks of its year compared to a year ago.

The company has benefited from the government's "Help to Buy" scheme which enables buyers with small deposits to access mortgage finance for low- to medium-value homes.

"It's working very well. The lenders are supportive of it and it really does deliver affordability for the buyer," Chief Executive Jeff Fairburn said in an interview on Wednesday. "It is also giving builders the confidence to continue to invest."

Persimmon said it had forward sales of 1.87 billion pounds for 2014, 35 percent higher than in 2013.

House prices in Britain are rising at their fastest since June 2010, up 9.1 percent on the year, according to official data released on Tuesday.

The figure masks wide disparities between the booming capital and the provinces. Prices in London are up 18 percent, the biggest jump since July 2007.

Fairburn said Persimmon was seeing welcome marginal price growth. "Generally throughout the country in our forward sales we've seen 0.5-1 percent price growth," he said. "We are starting to see some more movement on price and we'll keep a watch on it."

Its smaller rival Telford Homes, which is focused on London, said on Wednesday its pre-tax profit for the year to the end of March had more than doubled from the previous year.

"The London property market has remained buoyant, with demand from those wanting to live in London remaining well in excess of the supply of new homes," the company said.

It said the market in areas of London where it built - which excludes the prime city centre - was underpinned by a lack of supply and was still affordable to prospective owners and tenants.

Despite rising prices, many buyers needed to borrow less than 80 percent of the property value, it said, and it had still not made a sale through "Help to Buy".

Shares in Telford were trading up 4.8 percent at 353 pence by 0904 GMT, while Persimmon was up 1.7 percent at 1,287 pence.

(Editing by Brenda Goh and Tom Pfeiffer)

By Paul Sandle

Stocks treated in this article : Persimmon plc, Telford Homes plc