Each day in the run-up to the big day, you pop one basic grocery item - such as pasta, tinned food or toothpaste - into a cardboard box.

It was introduced in 1965 and continued as a mass-market grocery item until the late 1970s.

Most people visiting a variety discounter did so for so-called top-up shopping, but grocery items were crucial.

Grocery items have always been very price-sensitive because families buy them every week and so get used to what items cost.

In recent years a range of non-frozen grocery items has been added, and an extensive rebranding exercise was undertaken in 2009 to emphasise the company's value-for-money offering.