It was all change this week in The Grocer 33, with Tesco being crowned the cheapest retailer and Asda dropping to fourth-cheapest.

For the past four weeks running Tesco has been the fourth-cheapest retailer in The Grocer 33 survey as a result of the higher price of some of its fresh produce. However, this week it has swapped places with Asda, which previously enjoyed being the cheapest retailer for four consecutive weeks.

A £1.79 drop in the price of Hardys Stamp Shiraz Cabernet Sauvignon since last week helped Tesco to the cheapest position with a basket cost of £38.00. However at £1.38 each, its mangoes were 40p more expensive than Asda.

Tesco has also slashed the price of parsnips per kg by 40p since last week, bringing it in line with Asda's price of £1.48 per kg.

Our shopper noticed two promotions on items on his list, including a two-for-£2 deal on jars of Dolmio original bolognese sauce.

Sainsbury's was second-cheapest for the fourth time in as many weeks with a basket cost of £38.84, closely followed by Morrisons at £38.98. Asda limped in at fourth-cheapest with a £39.01 basket, followed by Somerfield at £42.74. Waitrose was the most expensive retailer with a £45.71 basket.

This week Asda raised the cost of a two-litre bottle of Fanta by 113%. At Morrisons the price of the same item rose 69% and Sainsbury's hiked its price by 100%.

Somerfield increased the price of 8-packs of Danone Actimel by 100% and the price of 200g tubs of Dairylea Spread by 98%.

But it slashed the price of 4-packs of Danone Bio-Activia by 38%. Our mystery shopper noted a two-for-£2.30 deal on 2-litre bottles of Coca-Cola.

Sainsbury's also continued its promotional activity by knocking 33% off the price of 75cl bottles of Jacob's Creek Chardonnay and 25% off 465g tubs of Mars Celebrations.

Our shopper also noticed a two-for-£2 deal on jars of Dolmio original bolognese sauce at Sainsbury's.