The estimated size of an oil find near Gatwick Airport has been upgraded to 100 billion barrels.
UK Oil & Gas Investments (UKOG) said the Horse Hill-1 well in the Weald Basin was now thought to hold 158 million barrels per square mile.
In May 2014, the British Geological Survey estimated the Weald Basin to hold around 4.4 billion barrels of shale oil.
UKOG described the find as a possible “world class” resource with the potential for “significant daily oil production.”
The company’s chairman David Lenigas, said it would create “many thousands of jobs” but cautioned that it would take a long time to begin production.
He said: “You’ve got to work through government process and to work with the local community. Everybody expects you to snap your fingers and all of a sudden the magic panacea is there. The key thing is there is a potential resource of significance here – but the fast track or slow track nature is really going to be determined by Westminster”.