Dig at Blick Mead, Wiltshire, a mile from Stonehenge, turns up bones of toad's leg dating to between 7596BC and 6250BC

If you're French, asseyez-vous, s'il vous plait. Archaeologists digging about a mile away from Stonehenge have made a discovery that appears to overturn centuries of received wisdom: frogs' legs were an English delicacy around eight millennia before becoming a French one.

The shock revelation was made public on Tuesday by a team which has been digging at a site known as Blick Mead, near Amesbury in Wiltshire. Team leader David Jacques said: "We were completely taken aback."

In April they discovered charred bones of a small animal, and, following assessment by the Natural History Museum, it has been confirmed that there is evidence the toad bones were cooked and eaten. "They would have definitely eaten the leg because it would have been quite big and juicy," said Jacques.

The bones, from a Mesolithic site that Jacques is confident will prove to be the oldest continuous settlement in the UK, have been dated to between 7596BC and 6250BC.

And it's not just toads' legs. Mesolithic Wiltshire man and woman were enjoying an attractive diet. "There's basically a Heston Blumenthal menu coming out of the site," said Jacques. "We can see people eating huge pieces of aurochs, cows which are three times the size of a normal cow, and we've got wild boar, red deer and hazelnuts.

"There were really rich food resources for people and they were eating everything that moved but we weren't expecting frogs' legs as a starter."

The discovery is entertaining, but has a wider importance, said Jacques, as it adds to evidence that there was a near-3,000-year use of the site. "People are utilising all these resources to keep going and it is clearly a special place for the amount of different types of food resources to keep them going all year round. Frogs' legs are full of protein and very quick to cook: the Mesolithic equivalent of fast food."

Jacques is senior research fellow in archaeology at the University of Buckingham which is funding a new dig on the site. He said it was looking increasingly likely that the site was the "cradle to Stonehenge" which was built around 5,000 years later.

Andy Rhind-Tutt, chairman of Amesbury museum and heritage trust, said: "No one would have built Stonehenge without there being something unique and really special about the area. There must have been something significant here beforehand, and Blick Mead, with its constant temperature spring sitting alongside the River Avon, may well be it.

"I believe that as we uncover more about the site over the coming days and weeks we will discover it to be the greatest, oldest and most significant Mesolithic home base ever found in Britain."