Delia is flavour of the month again at Waitrose?

When Delia Smith and Waitrose mutually parted company in January this year, the most famous faces associated with the supermarket became Heston Blumenthal (who had originally signed alongside Delia in 2010) and new Waitrose magazine columnist Pippa Middleton (who caused something of a stir).

Now it appears that Delia Smith is returning to the fold. But why, and do celebrity chefs really make a difference to a supermarket like Waitrose?