Heinz is playing on shoppers' nostalgia in a £2m TV campaign that claims its tomato ketchup is 'irreplaceable'.

The ad, which airs for four weeks from next week and will be followed by another four-week burst in August, carries the strapline 'It has to be Heinz'.

In an unusual twist, the ketchup bottle is not shown in most of the ad, which features people from a range of generations squeezing an invisible sauce from an invisible bottle on to their food.

"It reminds consumers that Heinz Tomato Ketchup is so irreplaceable that you don't have to see it to know what it is," said Mike Docherty, brand marketing manager. "Looking at how people add this final touch to their meals, it could only be Heinz Tomato Ketchup."

The tomato ketchup market has grown 16% to £152m in the past year, with Heinz accounting for a 76.4% share of sales, according to uSwitch data.