Marks & Spencer is bracing itself for a 3,000-strong demonstration by former employees at its flagship London store.
Thursday's rally, being organised by the TUC, is in protest at the company's shop closure programme across Europe.
Protesters are expected from France, Belgium, Spain, Portugal and Germany, where 39 M&S stores will be closed, with the rest of the marchers from the UK.
Demo leaders will demand the company consider the possibility of selling its European stores as a going concern.
A TUC spokesman said the rally will be peaceful and is not designed to paralyse the operations of M&S in London.
An M&S spokesman said the company's management has been in talks with employees in search of a mutually beneficial solution to the proposed store closures.
TUC general secretary John Monks said: "Our message to Marks and Spencer today is take your redundancies back.
"We call on governments throughout Europe - including our own - to support new information and consultation rights for people at work so redundancies don't come out of the blue."