The story seized the attention of investors, and the mainstream media.  Stephen Sanderson, UKOG chief executive, said the discovery was “very significant”, and “probably the largest onshore in the UK in the last 30 years, and we think it has national significance.” Sanderson speculated that between 1.5 and 15bn barrels could be recovered.

The claims of UKOG provoked immediate scepticism from some quarters, with Mike Jakeman of the Economist Intelligence Unit questioning whether the oil would ever be extracted. “The current price of oil means that only the cheapest oilfields are being exploited,” Jakeman explained. “Higher-cost ventures, such as Canada’s oil sands and off the coast of Brazil, are not economically viable at the current price level. This discovery falls into that category.”

The very existence of the oil was queried by Matthew Jurecky, head of oil & gas research for GlobalData. “UKOG’s estimates were very misleading,” Jurecky believes. He notes that UKOG’s claims were extrapolated results, based on findings produced by a single well. Jurecky states it is rare for oil formations to be “that homologous”, and does not believe “a single discovery can be extrapolated over a very wide area.”

“Conventional discoveries are more spotty,” Jurecky explains. “The single well results are almost certainly not repeatable over a large area. Even if they are, the development area would be severely restricted – and then consider above-ground factors, such as high development costs and public opposition to drilling activities.”

Now, moreover, UKOG seems to be quietly backtracking on some of its earlier, loud proclamations. A spokesperson for the company has announced that “the volumes estimated should not be considered as either contingent or prospective resources or reserves.”

At present, UKOG has a license over a site spanning 55 square miles – but the estimates cover an area of around 1,100 square miles. The firm has not undertaken work outside of its licence areas – and themselves admit that their investigations are “insufficient to comment on the possible oil in place in either the 1,100 square mile site, or the whole of the Weald Basin.”

UKOG’s climbdown was branded “another example of the potential for shale oil and gas being over-hyped by an industry desperate to start pumping profits,” by Brenda Pollack of Friends of the Earth – and many might be inclined to agree.