A protest is to be held outside Downing Street on Friday amid growing anger over revelations in the ‘partygate’ report over the way cleaners and security staff were treated.

Sue Gray said in her report that she learned of multiple examples of “unacceptable” treatment of security and cleaning staff during her investigation.

She wrote: “I found that some staff had witnessed or been subjected to behaviours at work which they had felt concerned about but at times felt unable to raise properly.

“I was made aware of multiple examples of a lack of respect and poor treatment of security and cleaning staff. This was unacceptable.”

Staff members “drank excessively” at the Downing Street Christmas party on December 18 2020, and a cleaner found red wine was spilled on one wall the next morning, the report said.

United Voices of the World (UVW), a union which represents cleaners and security guards in government buildings, has called the protest outside Downing Street.

The union said it was protesting against the culture of disrespect towards low-paid workers, such as cleaners and security guards, in government buildings and offices across London.

Petros Elia, UVW general secretary, said: “We’re not in the least bit surprised by the revelations in the Sue Gray report. We have thousands of members who work as cleaners and security guards and these workers face disrespect and discrimination on a daily basis in offices and government buildings across London, not just in Downing Street.

“It is outrageous to have rowdy and illegal parties during the pandemic but to then expect cleaners to mop up after you and to pay them, as well as porters and security guards, poverty wages and deny them full sick pay is abhorrent.

“Most of the cleaners and security guards out there are ethnic minority workers, Black, brown and migrant people, who are disproportionately impacted by poor working conditions and racialised inequalities.

“We represent cleaners at the Ministry of Justice (MoJ) who had to walk off the job during the pandemic because they were not given adequate PPE and were denied full sick pay, which they eventually won for Covid-19 absences.

“One of our members who worked as a cleaner at the MoJ tragically died an untimely and avoidable death. That’s how far the levels of disrespect and mistreatment went and goes towards low paid workers.”

A leading official of the cleaning industry is calling for a meeting with the Cabinet Secretary over the way cleaning staff were treated at 10 Downing Street.

Jim Melvin, chairman of the British Cleaning Council, said he was “appalled and upset” at revelations in Sue Gray’s partygate report.

Mr Melvin has written to Cabinet Secretary Simon Case, saying: “At a time when many cleaning and hygiene operational staff, arguably as frontline workers, were putting themselves directly at risk to maintain high standards of hygiene and ensure that key workers and the public were kept as safe as possible during the pandemic, it is absolutely appalling and upsetting to hear that they were being treated with such contempt by people who may sit within Government or the Civil Service and who frankly should know better.

“It is our position that cleaning and hygiene operatives are hardworking, professional and deserve to be respected in their vital work, just like anyone one else and certainly how the people concerned would expect to be treated.

“For further clarification and information, in some parts of the cleaning industry, the demand for increased standards of hygiene during the pandemic has combined with severe staff shortages to drive many colleagues close to breaking point.

“What cleaning staff need is support and recognition from the Government and Civil Service, not to be treated with any level of disrespect.”