Oxfordshire County Council's Trading Standards fears some shoppers will be "taken in by all claims of 50% off".

Ahead of the annual bargain hunt, it is advising residents to be a little more "sceptical" about price comparisons.

"If you see claims of 'up to 80% off', ask what was the original price?" a spokesman urged.

He said: "Shops may have kept the item on sale at the higher price at the back of their shop for a month.

"They can then claim a reduction against this price for the next six months.

"Would anyone have been silly enough to have bought it at the higher price?

"The item may have been on sale at the higher price at just one or two branches - a practice which has been commonly used by a number of large multiples."