The futures market has marked house prices down further following the release of the latest Halifax figures and now predicts a fall of 46% in cash terms from peak to a trough in 2011.

According to the Tradition Future HPI the price of an average house will plunge to £109,108 by November 2011 against the peak price of 201,081 reached in August 2007 – as measured on the non-seasonally adjusted Halifax index.

Prices, says Tradition, are not forecast to rise until 2012.

So, if we assume we are not struck by a nasty bout of deflation and that general prices rise on average, say, 2% a year, that would put the price of an average house in real terms at roughly half its peak value.

Futures markets are used for hedging, so there can be a tendency towards the outer fringes of likelihood.

But what is for sure is that investors are becoming increasingly downbeat about the housing market each month.

As recently as August the market was calling the bottom at £137,695 in 2011. Today the bottom is below £110,000.

So someone is making a happy penny out of plunging prices and there could be a bit of speculation pushing the market further south than it might otherwise go.

I must confess that I have been safely in the bear camp on house prices for some years. But this kind of drop is well outside what I thought likely, even though I may have accepted that theoretically it was always a possibility.

However, as the Tradition press release points out, the FT Lex column recently noted: “House price derivatives markets are not perfect guides to the real thing. They are often illiquid and dominated by mortgage banks seeking to hedge an element of their housing exposure. But, so far, they have had a better predictive record than most economists.”