The RMT transport union has called a protest against the contracting out of cleaning on London Underground for Wednesday of next week.
The contract for the Bakerloo, Victoria and Central Lines is set to be renegotiated.
It is believed that a company other than the current ISS contractor will receive it.
Cleaners, many of them migrant workers, are sick of being handed around from company to company, and facing poor pay and conditions.
The RMT union has called a protest in their support at the headquarters of the Metronet part of London Underground, which is responsible for the contract.
It is asking as many people as possible to come and back them.
Protest 12 noon, Wednesday 18 November, Templar House, 81-87 High Holborn, London WC1V