THE battle for supermarket supremacy gained added impetus yesterday with the announcement that Sainsbury's will open 100 convenience stores across the country.

The store chain has joined forces with Shell to develop the outlets at petrol stations and will create 2,000 jobs in the move, which is seen as a rival to Tesco's Express stores.

Tesco beefed up its attack on the £20bn-a-year convenience market by saying it would convert 450 of the 870 T&S Stores it acquired in October to Tesco Express formats during the next four years.

The supermarket industry has been in turmoil following Morrisons' speculative bid to buy Safeway.

The outcome of the resulting bidding war is still in the hands of competition commissioners, and a decision is not expected until August at the earliest, but the move forced Morrisons' competitors to reassess their standing in the market.

Sainsbury's successfully trialled its latest strategy at six venues in the South-East, where it combined Shell's branded forecourts and Sainsbury's local store format.

The pair expect the 100 new outlets to open within three years, although details of where they will be have yet to be announced.

Sainsbury's began the trials in October 2000 and has seen three of the outlets feature in its list of top 20 performing stores. The new stores will sell a range of products by both companies.

Chief executive Sir Peter Davis said: "We believe our convenience store offer is the best in the UK and by working with Shell we can bring Sainsbury's quality, convenience food shopping into new areas of the UK."

Sainsbury's and Shell hope to begin the changes in the autumn.

Sainsbury's recently created 10,000 jobs in an effort to cut queuing time at its checkouts. The initiative, launched in April, has seen "encouraging results".

Sir Peter, who took over at the group three years ago and will take the chairman's post in March next year, is part-way through a recovery drive aimed at closing the gap on market leader Tesco.

Anthony Platts, retail expert at North-East stockbrokers Wise Speke, said: "Sainsbury's is aware that it has very little chance of getting Safeway so it is taking pre-emptive measures by moving into what would appear from the trials to be a very lucrative area of the market."