Fresh fruit and vegetable prices continued to fluctuate in this first week of December. The cost of parsnips has risen by an average of 11% in the past seven days, and now rests at £1.82 for a kg.

The largest increase took place at Asda, where the cost leapt by 89%, from 0.99p to £1.88. Somerfield joined the fray, with its parsnip price climbing from £1.99 to £2.28, making it the most expensive of the top six for 1kg. Tesco had already adopted the higher price of £1.88 the week before last.

Courgette prices have also rallied at Sainsbury's, Somerfield and Waitrose, while the largest decrease of the week was seen at Asda and Morrisons where the retail price of cherry tomatoes plummeted 25% and now costs 59p for a 250g pack.

A look at this week's shopping list also reveals Asda has further reduced the price of its whole cucumber.

Asda has made a number of price cuts this week and is currently providing the cheapest shopping basket of the six by a comfortable margin.

This week's mystery shopper spotted four mulibuy deals at the retailer's Burgh Heath branch.

At £41.58 the cost of Asda's basket is 87p cheaper than Sainsbury's, which provided the second-cheapest shopping basket, ahead of Tesco.

As Christmas draws ever closer we are also seeing an increase in the number of confectionery items on promotion as the supermarkets vie for the stocking filler pound.

Many of the retailers are carrying bogof deals on After Eights, present on this week's list, while the price of Haribo Starmix has also fallen by an average of 7.6% points.

Morrisons was the fourth-cheapest retailer for this week's 33 items, while Waitrose was once again in fifth place ahead of Somerfield.

The chain, which claims it has cut thousands of prices as part of its aim to become "Britain's favourite grocery shop", is once again the most expensive retailer on our list.