The gap between the cheaper retailers and the Grocer 33's costliest couple has grown to a whopping £8.44 this week as the price cutting tactics of the top four really start to kick in.

Asda, the first to slash its prices, is already consolidating its position as the UK's cheapest supermarket with a fourth consecutive week in the top spot since it won The Grocer 33 Gold for the lowest prices.

Its £58.14 basket contained the cheapest Smirnoff Vodka at £11.98.

By comparison, it was £13.29 at Morrisons and £14.99 at Tesco.

Another differentiating factor was the price of red seedless grapes. Asda and Tesco cut their prices this week, although Asda still had the cheapest offering at £1.98. Its basket total would have been even less had it not added 20p to the kiwi fruit's price tag.

Morrisons also appears to be fulfilling its promises by either freezing or lowering its prices across the list. It gained ground on Asda with a basket total of £58.85. While Asda and Tesco kept their own-label beef rump steak at £8.98 this week, Morrisons was offering it for only £7.00.

Sainsbury's is the third-cheapest retailer with a £61.66 basket. It's McCain Smiles were 31p less than last week and its carrots and onions were also cheaper. Sainsbury's also froze the price of Smirnoff Vodka to keep its total down.

Tesco didn't fare so well with the vodka - and must regret increasing its price from £11.98 to £14.99 - the joint highest on the survey. It also added £1.58 to its own-label beef mince, but lowered the red seedless grapes by £1.01.

Waitrose did not help itself by increasing the price of its red seedless grapes by 50p, although it did offer the cheapest Batchelors Super Noodles.

Somerfield has the highest prices for a second week with a £71.94 basket. It too increased the price of red seedless grapes by 50p from last week. Somerfield's decision to increase the Smirnoff Vodka by £2 anchors the retailer in the most expensive position.