Waitrose has seen a "phenomenal" uplift in sales of its packaged cake lines, following an overhaul of pack design, the addition of new lines and changes to recipes, including a complete switch to free-range eggs.

Cakes buyer Sam Witherington said the revamped range, which launched into stores on 19 May, has helped Waitrose’s packaged cakes see almost a 30% uplift across the range.

Witherington admitted she was "surprised" by the boost to established product lines from introducing a minimalist layout to the packaging. "Suddenly there’s a 10 - 11% increase in sales, just because the customer can see what they are buying, read about the products and can see why they are spending their money."

The lines are now undergoing a second stage of promotions, which will last until early August, to help encourage customers to buy into the range.