Marks & Spencer is understood to be on the hunt for up to 200 extra convenience stores as it looks to ramp up expansion of its Simply Food offering.

The high street favourite outlined plans in November to open 200 of the small format stores by 2016, but M&S is now thought to have ordered property agents to hunt for 200 more.

"The food side of the business has been going brilliantly. It's looking to capitalise and will push hard and is now on the look-out for up to 400 new stores overall by next year," a person familiar with the matter told IBTimes UK.

M&S has around 450 convenience stores, which includes franchised outlets.

Sales at the firm's food division have seen 22 consecutive quarters of growth, contrasting the fortunes of major British supermarkets who have all seen sales drop, leading under-fire chief executive Marc Bolland to hail an "excellent performance" in April.

Last month M&S reported growth in its clothing and other non-food merchandise sales for the first time in nearly four years.

It is also thought that M&S is considering smaller than usual stores as part of the expansion.

One source said: "M&S is looking at different models and ideas, and management is now happy to follow the smaller convenience store model rather than opting for mid-size stores."

A spokesperson for M&S said that it did not comment on speculation.