Shoppers will "scrimp and save" even more in future, according to research by PwC that will be unveiled tomorrow at the Checkout magazine annual conference.

It found that 65% of people "are now buying 'clever' and spending more time hunting for value; over half are buying less and over a third are trading down or buying cheaper products".

All retailers expect both the volume and value of goods sold to shrink and "everyone is looking over their shoulder at competitors at the moment, even Tesco", said David McGee, a director at PwC.

"Value started in 2008 when the customer was voting with their feet. The trade realised they had to respond aggressively," said McGee.

He said the retail market has changed forever because shoppers have traded down.