The strikes by almost 300 cleaners, porters, stores operatives and food service assistants will run from 9-11 September.

Unite general secretary Sharon Graham said: ‘Guy's and St Thomas' is one of the country's biggest NHS trusts but is treating its staff with utter disdain. They cannot survive living in London on poverty-level wages. Alongside multiple other failures of management, our members have been left with no option but to take strike action. 

‘Our members are the backbone of the hospital - keeping it clean, feeding patients and staff or keeping the public safe - but they are paid barely above the Minimum Wage. This cannot continue and they have the full support of their union in this dispute.'

The union accused management of failing to address long running complaints, including racist and bullying behaviour by facilities management, issues over bank contracts and hours, a failure to provide adequate welfare facilities like showers or changing facilities and the failure to provide adequate safety equipment to security staff.

Highlighting pay levels were set by the NHS and not the trust, a spokesperson for Guy's and St Thomas' said: ‘It is unfortunate that Unite has called these strikes in the middle of ongoing negotiations.

‘We would urge them to call off this action so we can continue making progress on a fair deal for our highly valued staff.'