A shortage of land for sale in the county is driving prices higher, according to an expert. Giles Wordsworth, head of estates and farm agency, based in Smiths Gore’s Oxford office, said low availability was causing strong competition for available plots.

He added: “October to December is traditionally the quietest quarter but this year we have not seen such low levels of supply since 2005, according to the latest figures from our research department.”

Both base and equipped values have continued to rise, but the outlook is harder to predict, according to Mr Wordsworth.

“We expect to see a negative effect on the market from the proposals for the Common Agricultural Policy after 2013, as they would put UK farmers at a disadvantage compared with farmers elsewhere in Europe,” he said.

“But changes to planning rules which would encourage development in the countryside along with reform of the planning system, could boost values.”

Values for equipped farms have increased five per cent since October 1, on top of a seven per cent increase in values between July and September.

The overall annual increase stands at 14 per cent. Bare land values have also soared by 14.5 per cent over the year.