Marks & Spencer plans to develop a full online food delivery service, its commercial director of food has revealed.

During a speech in which he sensationally branded the retailer "complacent" and "fat", Jim Waller said online was "the way to become more than just a top-up shop".

M&S was considering adopting a model similar to Waitrose and Ocado, he told delegates at an industry networking event last week. "Whether we do it with a partner is up for consideration," he said, adding that online food retail was the most dynamic part of the grocery market.

"We can't afford to bury our heads in the sand about online," he said. "But if you're going to put together an online operation, you need to provide a full grocery offer."

Waller would not give a time scale, but said it was unlikely to happen this year because of the logistical complexity involved.

It was just one avenue M&S was exploring in a bid to improve its offer. As economic conditions deteriorated, M&S would be looking to Project Genesis to keep a lid on prices, he said.

"We should be the best product on the market. I don't think every time we give that to the customer because we've been concentrating on other things for the past two years," he said. "We've grown complacent and fat. We need to change that and find cost savings. "

Tightening financial conditions were a big challenge because 70% of trade came from premium ready meals, said Waller. "The credit crunch is hitting people's wallets and that is hitting us," he said. "We have to deal with people who say Tesco Finest is good enough, do I need to do a second shop?"

For commodity items such as dry pasta and milk it was seen as "very poor value for money", he admitted. "Where there is a point of difference, such as with melt in the middle chocolate pudding, we are seen as good value for money."

The company denied it had any concrete online plans. "There is no prospect in the short term that we will be going online with food," a spokeswoman said.