Tesco is aiming to grab another £2.5bn of sales in the UK as it teams up with wholesaler Booker to sell its products to independent corner shops, restaurants and cafes.

The UK’s biggest supermarket unveiled the plan as it announced a 28% rise in operating profits, bolstered by better than expected sales growth in the last three months of its financial year.

The UK’s biggest retailer said it made a pretax profit before exceptional items of £1.64bn in the year to 24 February as total group sales rose 2.8% to £57.5bn. Sales at established UK and Irish stores rose 2.4% in the final quarter, slightly ahead of the 2.2% expected by analysts.

Dave Lewis, the chief executive, said: “This has been another year of strong progress, with the ninth consecutive quarter of growth. More people are choosing to shop at Tesco and our brand is stronger, as customers recognise improvements in both quality and value.

“We have further improved profitability, with group operating margin reaching 3.0% in the second half. We are generating significant levels of cash and net debt is down by almost £6bn over the last three years. All of this puts us firmly on track to deliver our medium-term ambitions.”

The update is the first since the completion of Tesco’s £3.7bn takeover of the grocery wholesaler Booker last month. Booker’s former chief executive Charles Wilson has taken over as head of Tesco’s UK business.

Lewis said the deal would bring about cost savings and a potential £2.5bn in extra sales from joint projects.

Tesco has already begun testing a mini version of Booker, badged Chef Central, at one of its supermarkets and is considering using its home delivery vans to serve Booker’s clients, which include restaurants and independent convenience stores.

Wilson said there were about 100 Tesco locations which could be suitable for Chef Central because Booker did not have a cash and carry nearby. Tesco is also rumoured to be planning to test a new discount chain or family wholesaler similar to Costco. Lewis declined to comment on those rumours.

Tesco is also testing selling 30 Booker products, such as catering-size bags of rice, on the shelves supermarkets, while Booker is adapting 30 Tesco products, such as ready-made mash, for wholesale to its thousands of convenience store clients. The products will be made by Tesco suppliers but sold under different brand names.

Despite rumours that Lewis might be tempted to leave Tesco and hand over the top job to Wilson, he indicated he planned to stay on. Lewis said he was “looking forward to [Wilson] and I and the whole team working together over the coming years”.

Despite “difficult circumstances”, which include a tough UK market and an inquiry by the Serious Fraud Office into accounting problems dating to 2014, before Lewis took charge, the Tesco boss said the company was “slightly ahead of where we thought we might be at this stage”.

He said Tesco was still a work in progress. “It is definitely not job done … but we have to take comfort from what we have done,” he said.

According to the latest market share data from Kantar Worldpanel, the UK’s biggest supermarket chain held a 27.6% share of the market in the first 12 weeks of the year, unchanged from the same period in 2017.

Lewis pointed to a “really strong” performance on food, which he said was the engine of growth. He said Tesco had gained market share on food in the UK over the past year as food sales had risen by nearly 3% in value, although the volumes rose just 0.7%.

He said there was growth across the business with sales at Tesco’s largest stores, which had been hardest hit by changing shopping habits, up 2.3% in the final quarter. Online grocery sales rose 5% but non-food sank 11.3% online and 0.4% in established stores..

The step up in performance came despite a softening in food inflation from about 3% to 2.4%. Lewis said food inflation had dropped to just 0.8% in the last month.

The strong performance in the UK was offset by difficulties in Asia where underlying sales slid 14% in the fourth quarter – a deterioration from the 9.6% seen in the previous three months.

Lewis said the fall was partly linked to a change in strategy away from unprofitable bulk sales and discount coupons.