Lidl, in its first appearance as a guest retailer, has taken an easy victory - beating its nearest big four rival by 15%. It was £8.60 cheaper than second-placed Morrisons, and only three products could be found cheaper elsewhere - the cauliflower at Asda, and the Chicago Town pizza and Laughing Cow cheese at Morrisons.

The discounter was helped by the fact it had seven price-only promotions, four more than second-placed Morrisons.

Morrisons beat Asda to second place by £2.12 - it is the fourth time since the new Grocer 33 year kicked off in June that it has come in cheaper than its rival. In contrast to previous years when Asda has dominated, the two supermarkets are currently running neck-and-neck with three victories each. Two significant price promotions, offering £1 off PG Tips and £1.19 off Chicago Town pizzas, helped make the difference this week.

Although £2.12 more expensive than Morrisons this week, our Asda shopper left with a £3.31 money-off coupon.

Behind Asda, there was a £3.78 gap to fourth-placed Tesco, but our shopper had the consolation of a £2 voucher.

It was then a small 77p gap to fifth-placed Sainsbury’s. Yet it offered a money-off voucher for just 26p.

Waitrose was last. With a basket costing £71.84, it was £22.61 more expensive than Lidl.