A union has issued a formal complaint to the Homerton Hospital cleaning staff contractor over alleged intimidation by a senior manager at a protest.

GMB say the staff member for firm ISS turned up at a demo held by workers outside the hospital on January 20 and got out his mobile phone.

The protest was over the treatment of staff at the hospital, with the union citing bullying, harassment and a sick pay policy "so draconian one hospital worker had his pay docked after suffering a stroke".

It says ISS refuses to honour NHS terms and conditions for its staff working as domestics, porters, catering and security staff. They are not paid for their first three sick days, and the union says they are forced to come into work instead - putting patients' and colleagues' health at risk. GMB wants the £45million contract brought back in house.

Spokesperson Lola McEvoy said: "Our members know their rights and they're absolutely allowed to exercise them by protesting without intimidation. It's symptomatic of a toxic culture that a manager would show up to a protest and try and deter his staff from taking part - but this behaviour only makes us stronger and the staff's patience is wearing thin."

The union is also annoyed at the Homerton Hospital Foundation Trust for not committing to a meeting between its bosses and the workers. The hospital says it won't do so because the workers are employees of ISS and not the NHS.

"It's a real shame Homerton have taken this approach, they're denying those who clean their hospital the basic dignity of having their voices heard," said Lola. "We understand their need to hear all sides but wish they'd been as considerate to the cleaning staff when selling their sick pay, overtime rates and pensions, to the lowest bidder."

At a town hall meeting last month Homerton CEO Tracey Fletcher said the hospital would be challenging ISS on some of its practices, but said bringing the contract back in house could "not happen overnight".

A Homerton spokesperson said: "We have been talking to ISS and will seek detailed and documented assurance they are meeting the legal requirements and employment good practice in relation to the issues raised.

"Where that assurance cannot be provided or is not sufficiently robust we would consider this serious and would require ISS to immediately address this."