The Occupy London movement has announced plans to "occupy" the underground transport network on 1 May.
On its website Occupy said the event would be "fun and inspiring".
"As May Day is a day for all workers, Occupy supporters are planning ‘Occupy the tube’, a fun and inspiring event starting on Tuesday morning in the centre of the City of London. All will be revealed that morning but look out for white flowers," the group said.
"On the day, meet from 7am at the Finsbury Square occupation, or 8am at Liverpool Street Station. Wear your best workwear and bring white flowers. Musicians, performers and artists also welcome, as are donations of white flowers, which can be left at the Finsbury Square occupation prior to May Day.
"This event is for everyone, including – and especially – those who have followed Occupy over the last seven months but have never felt able to participate in any direct way."
Further details of the plan have not been revealed, but members are said to be planning the operation as part of a week of May Day demonstrations and protest events.
Planning for the event is currently taking place on Facebook and at meetings being held close to the group's former campsite at St Paul's Cathedral.
A meeting scheduled to be held on the St Paul's steps on Wednesday was said to have involved discussions of the stunt.
Occupy members denied that there would be an attempt to stop the Tube.
The Occupy London movement has been relatively quiet since it was evicted from the St Paul's site on 28 February, more than four months after it began.
Other events planned for May Day include a march from Clerkenwell Geen to Trafalgar Square, where protesters loosely linked to the movement briefly attempted to form an impromptu camp during widespread protests in November.
The group is also calling for strikes across several industries in support of fair work policies.
"This May Day, strike with your union if you have one. Call in sick, take a holiday, don’t show up," the group said.
"Join actions and marches in your city, bring your community together and talk about the issues in your area, make some noise. Remember, you are not alone and that together we can make a change."
Requests for comment from an Occupy London spokesman were not returned as of press time.