Property investors have seen the value of their portfolios dip again after property prices in both England and Wales fell for a third consecutive month in September.

All in all they have lost half of the total gains they made in the first six months of the year, a new survey has revealed.

Property website Rightmove, which claims to capture 90 percent of all homes put up for sale across both countries, said asking prices fell by 1.1 percent this month, following previous drops of 1.7 percent in August and 0.6 percent in July.

Meanwhile the annual rate of growth slipped down to 2.6 percent from 4.3 percent. Rightmove’s findings seem to reflect data from other surveys, which show house prices have stumbled in recent months.

This is something commentators have blamed on increasing supply and nervousness ahead of large government spending cuts.

However, supply pressures eased in September, according to the Rightmove survey, with the number of properties coming on the market falling to its lowest level since April.

Miles Shipside, Rightmove's director, said September's survey could be interpreted in many different lights.

“The ‘double-dippers’ will be able to point to a clear downward trend, with new sellers dropping their asking prices for three months on the bounce,” he explained.

“Conversely, we are also recording the lowest weekly run-rate of fresh sellers since April.

“This will give some ammunition to those forecasting a flatter price trajectory as it could be an early sign of fresh supply beginning to wane.”

Another factor that could be contributing to the tremulous market is the decline of mortgage lending.

During August loan levels dived to a 10-year low for the month as activity in the housing market remained weak.

A total of £11.4 billion was advanced during the month, 14 percent down on July's figure and the lowest level for August since 2000, according to the Council of Mortgage Lenders (CML).

The group has warned that the market is heading for a ‘difficult’ second half of the year, with lending volumes likely to remain below the level seen during the last months of 2009, when activity was buoyed due to the end of the stamp duty holiday.

Figures suggest the drop in lending may have been caused by a fall in the number of people remortgaging during the month.

The Bank of England said data from major lenders suggested that net lending, which strips out redemptions and repayments, was ‘little changed’ during August.

It added that while gross lending for house purchase was broadly stable during the month, remortgaging activity continued to be weak.

Net lending looks set to remain subdued during September, with lenders reporting a slight fall in the number of mortgages approved for house purchase in August, with these reaching their lowest level since April 2009.

Mortgage rates for new customers fell slightly during August following an increase in competition in the market.

But in its quarterly bulletin, the Bank of England said banks had not been passing on the fall in the base rate in full to borrowers, with the interest rate charged on some loans rising.

It said this was due to banks currently facing higher borrowing costs themselves, as well as an increased risk of homeowners defaulting on their loan.

But it added that banks were also charging higher margins in a bid to shore up their balance sheets.