Talk to almost anyone you can think of about house prices, and they will all say that there is one way for them to go – up.

Hometrack, the RICS, lenders and estate agents all widely predict that house prices will continue to rise, as shortage of supply keeps the pressure up.

Most predict rises for the next five years, while Santander think they will more than double in the next 15 years.

However, what’s the betting down the bookies?

Jamie Loughead, head of politics at bookmaker Star Sports, believes property prices will go down, on an annual basis, by next January.

He rates the probability at 54.9%.

But what exactly is a price decrease, given that the ONS, Land Registry, LSL, Halifax and Nationwide all quote entirely different prices – while the RICS never gives any prices at all?

Furthermore, what about our old friend seasonal adjustment, which means that most of the figures are mysteriously massaged in an upwards or downwards direction by economists, not to mention

the habit that publishers of house price data sometimes have of changing their figures in subsequent months when they have another go at seasonal adjustment?

Loughead will be going by what the Nationwide says next January 8 and – according to a report in Business Insider – compare it with £196,930.

In fact this was the not seasonally adjusted figure that Nationwide gave for February, so we rather wonder what Loughead will actually be comparing.

It is also worth noting that next January 8, Nationwide will presumably be reporting on house prices the previous month – ie December.

In December 2015, Nationwide reported an average price of £196,999 – again, not seasonally adjusted.

Nationwide do, however, revise the percentages of growth or otherwise once they re-estimate seasonal adjustment. This could get complicated.

On February 8 this year, Star Sports gave odds of 8:11 that house prices would go down by next January, and odds of 11:10 that they would go up.

For those not of the betting persuasion, it means that if you bet on house prices rising, you would actually win more than if you bet on them falling.

Over the last few weeks, Loughead has become more convinced that house prices will fall.

The odds are currently 8:13 based on a 58.2% chance of prices falling, and 5:4 based on a 41.8% chance of house prices going up.

The reasons for Loughead’s thinking? Chiefly the buy-to-let Stamp Duty surcharge, global uncertainty and falling foreign investment.

And how much does he think they will fall? Right now, he’s suggesting 5%.

As for Nationwide itself, it does not believe house prices will fall, but is expecting a rise this year of 3–6%.

Odds, anyone?