Waitrose boss Mark Price is expecting to deliver the highest operating margin of all the major food retailers this year, after reporting a bumper increase in half-year profits today.

The upmarket supermarket reported a 28.9% increase in operating profits to £142m for the six months to 28 July. That came alongside a 2.2% increase in like-for-like sales, as total turnover grew by £172.8m to £2.8bn.

The sharp increase in profits was partly due to the favourable comparison with last year, when Waitrose made costly investments in convenience, waitrose.com and stores in the Channel Islands.  But Price said the important figure was the operating margin, which he claimed led the grocery market.

“If you look at The Grocer’s table of the top 100 grocery retailers this week, our 5.4% operating margin is well ahead of the market,” he said.

“I’m confident that by the end of the year we’ll have the highest operating margin of all the major food retailers in the UK.”

Waitrose also reported a 50% increase in online sales for the half-year – boosted by the revamp of the website made in March last year and opening of a dark store in Acton, London.

It was also a good six months for Waitrose parent the John Lewis Partnership. Profits before tax rocketed by almost 47% to £163.5m. Total sales grew 8.7% to £4.4bn.

Waitrose and John Lewis have been working closer together over the past year, with John Lewis products now available through click & collect at most Waitrose stores.