Supermarket chain Waitrose is to open 20 “Little Waitrose” convenience stores in and around London over the next 18 months as it goes head-to-head with Marks & Spencer on the high street and Ocado online.

Waitrose is due to open a convenience store in Tottenham Court Road, London, next week.  Waitrose has an eventual target of 300-400 convenience stores across the UK.

Waitrose managing director Mark Price told the Financial Times: “We are formally going to put the foot on the gas. We are rolling this out and now we want as many sites as we can get all over the country.”

He added: “The focus in the first instance is inside the M25.”

Price said with the London expansion he is looking to bolster market share within the M25.

The grocer is also looking to open Waitrose cafes on high streets. By the end of 2013, it plans to have 90 cafes in Waitrose stores.

Last month Waitrose kicked off a marketing campaign within the M25 emphasising its service and free delivery on orders over £50, as it takes on Ocado.