The Horse Hill well near Horley in Surrey found oil in three unconventional rock formations, according to the results of analysis released yesterday. Anti-fracking campaigners say it confirms their suspicions about the site near Gatwick Airport.

Last year, UK Oil & Gas Investments announced a much smaller find of oil in the Portland sandstone. But yesterday, it said analysis by the American company, NUTECH, had revealed 407ft of potential oil pay in the Kimmeridge formation. It also confirmed a further 73 feet of potential oil pay in the Oxford Clay and Middle Lias formations.

Stephen Sanderson, UKOG chief executive, said the well “penetrated a very thick section of world class, thermally mature, oil saturated source rocks in the Kimmeridge section encasing the Kimmeridge limestones”.

He said: “The richest section, and possible sweet spot, lies between the base of the Upper Limestone and Top Lower Limestone at 2931-3084 ftmd with an average of 5% TOC [total organic carbon] and a high of 9.4% TOC.” (2% TOC is regarded as a good source rock.)

Last month, Mr Sanderson told a presentation for investors in London the Kimmeridge Clay at Horse Hill looked at least as good for oil as the North Sea, if not better. (our report). During that meeting he said: “The big thing that we find from Horse Hill is the fact that the Kimmeridge Clay is not just fully mature but it’s actually within the peak oil generation window.”

UIKOG has always said it would not frack at Horse Hill. In October last year, David Lenigas, chairman of UKOG, told BBC Surrey the Horse Hill: “I am a landowner and the farmer as well in the UK. I would not want fracking on my land and I certainly would not be doing fracking in Horley. I can absolutely guarantee that”. He added: “I have publicly stated in an open forum that there will be no fracking at the Horse Hill site.”

But last month, Mr Sanderson hinted that UKOG was interested in unconventional, as well as conventional, development. “Big bits of interest for the future for us in UKOG and for the rest of the UK is really in the centre of the [Weald] basin in hybrid plays, which are a combination of conventional and unconventional and also maybe unconventional.

This appears to be confirmed by yesterday’s announcement. Analyst Barney Gray told Proactive Investors: “The work conducted by UKOG and NUTECH has significantly broadened the scope of the HH-1 well with the identification of three promising unconventional formations in addition to the existing conventional Portland sandstone reservoir”.

For anti-fracking campaigners this confirmed their suspicions about Horse Hill and UKOG. Vanessa Vine, of Britain and Ireland Frack Free, said: “Another example of how this industry tries to mollify us with reassurances of it only being conventional extraction.

“Six months ago, there was no way they were going to frack this site in Surrey. And then suddenly, ooh look! Lots of lovely “world class” oil we didn’t expect to find, that unfortunately we can’t extract without fracking. Oh, what a surprise!! Not.”