Premium frozen food ­retailer Cook has declared its decision to extend Sunday opening hours to all its stores a success.

Sunday sales at Cook's 48 stores have leapt £1,006 to £11,229 since 15 May.

"It's only been a couple of weeks but the sales already have been promising and we think it's something that's really going to work for us," a spokeswoman said. "We've been tentative about it in the past but decided to just go with it and to raise awareness across the board about Sunday openings."

Twelve of Cook's 18 franchisees have also decided to open on Sundays.