Teesside-based Bells Stores will play a key role in Sainsbury's strategy to improve its flagging sales, it was revealed yesterday.

As the supermarket unveiled its strategy for success, under the banner "Making Sainsbury's Great Again", it reinforced its commitment to the convenience market which it hopes will be a key growth area over the next few years.

Sainsbury's bought convenience chain Bells Stores for £22m in February and is planning to expand from 54 to 80 shops by the end of next year.

Chief executive Justin King said his first move would be to recruit 3,000 shop floor staff in all stores - including 450 new staff in the North-East - as part of his strategy to grow sales by £2.5bn over three years.

As well as the extra staff, workers will be offered a bonus scheme to reward them on store standards and availability of products. In a bid to cut costs elsewhere, about 750 head office jobs will be lost by March.

With the company believing profits can be improved through sales rather savings, Sainsbury's will invest £400m on its offer to customers.

The need for an overhaul was highlighted by forecasts from Sainsbury's showing underlying profits for the first six months of its financial year would be down by two-thirds at between £125m and £135m.

It also said its focus on fresh and own-label products would be stepped up, particularly through Taste the Difference and Be Good to Yourself brands.

Formats will be simplified with Sainsbury's Central and Savacentre stores becoming part of the company's core supermarket and convenience store estate.

Sainsbury's said its convenience format - which includes Sainsbury's at Bells Stores - was trading well.

Bells chief executive Steven Bell was called away to Sainsbury's for meetings this week to discuss the strategy.

All Bells Stores, which employ more than 1,000 people in the region, will be rebranded to Sainsbury's at Bells Stores by next year, and will stock more than 500 of the supermarket's brands, as well as keeping many of its own offers and goods.

Fresh fruit, vegetables and chilled foods will be supplied by Sainsbury's, as well as bread and milk, which will keep prices low on those items.

It is already expected to increase its workforce by more than 50 per cent - but a Sainsbury's spokesman said it was not clear whether those jobs would be included in the extra 450 for the region announced yesterday.