The figures behind the Jockey Club’s proposed sale of Kempton Park for housing development have never quite made sense; probably because they have not shown the full picture.

Two weeks ago Roger Weatherby, the senior steward of the Jockey Club, said that the sale of Kempton would need to earn the Jockey Club at least £200 million to be viable.

That was double the figure that the club had put forward when it first announced its plans but what they have not made public is that the club do not wholly own the rights to all the land which would be on offer and, according to a document dating back 12 years, there would have to be split over a portion of any proceeds with other parties.

The more one looks at the club’s much-vaunted 10-year plan to invest at least half a billion pounds into British racing, the more it comes across as two of Joseph Stalin’s five-year versions stitched together.

And the seams do not appear to be holding that well.

Last month Jockey Club Racecourses announced its intention to sell Kempton Park for housing redevelopment and that the estate had been submitted for consideration following the local authority's “Call for Sites” to address local housing needs as a joint-venture with Redrow Homes to build 3,000 dwellings on the site.

“If development is permitted, the Jockey Club will be looking to ensure it generates in excess of £100m for investment in British racing,” it said originally, presumably with the intention that such an impressive headline figure would take away the breath and dissent of the racing community.

The only problem is that, thus far, the figures and the reasoning behind this project have stacked up about as well as the leaning tower of Pisa.

The latest estimate of land value by the Department for Communities and Local Government in the Spelthorne Borough Council area, where Kempton is situated, is £4.97m per hectare, which values the 230-acre site at Kempton at around £462m.

Viewed through local property prices, the average value in Speltorne is approximately £408,000 so, if the proposed 3,000 dwellings were sold for an average of £300,000, that still puts the deal at £900m.

Industry sources suggest that, as the landowner, the Jockey Club could expect to take at least 30 per cent of the top-line figure.

That made the Jockey Club’s own figure of £100m look the far side of conservative; the worst bit of land trading since Manhattan Island was sold for $24 and a box of trinkets. Or perhaps those behind this scheme had been factoring in that the club does not wholly own the rights to all the land.

In 2005 Spelthorne Council sold its leasehold interest in two parcels of land on the Kempton Park estate for £499 999, with a covenant stating that if the land was developed or permission for development was granted before 2030, then the council would be due one-third of the difference between the value of that land when permission was granted and the earlier valuation.

The remainder would be split equally between the Jockey Club and the Horserace Betting Levy Board who sold the track as part of the United Racecourses group – also including Epsom and Sandown Park – to Racecourse Holdings Trust, the forerunner of Jockey Club Racecourses, for £30.25m in 1994.

The two parcels of land measure 43.12 acres so the Jockey Club face having to hand over almost two-thirds of the proceeds for nearly 19 per cent of the land that would be sold.

All of which may explain why the Jockey Club had been working to such low estimations of their potential profit.