British retail giant Marks & Spencer revealed on Monday that some of its biggest stores will be open 24 hours a day in the run-up to Christmas.

The firm said it had taken the decision in response to customer demand but had not yet settled on which stores would be open around-the-clock.

An M&S spokeswoman said: "Last year a number of our stores opened until midnight and some are now open until then anyway. Customers want flexibility in terms of when they can shop, it is meeting customer demand."

Meanwhile, the company has dismissed as speculation reports that chairman and chief executive Luc Vandevelde is planning to step down as chief executive but remain chairman of the group.