They also allegedly smuggled uninvited and unvetted guests into royal garden parties, arranged cover for each other to sleep while on duty and slept in private areas in Buckingham Palace, Southwark Crown Court in London was told.

The allegations were made by John Cooper, defence counsel for former royal protection officer Paul Page, who is accused of conning colleagues and friends to fund a life of luxury.

They came during a lengthy cross-examination of Sgt Adam McGregor, a former colleague of Page in royal protection who left service at Buckingham Palace in 2005. He has accused the former officer of "conning" him out of thousands of pounds.

In the exchanges Mr Cooper said he "suggested" there had been a procedure among armed officers at Buckingham Palace whereby one officer on duty might sleep while the others kept watch in case their superior catches them out.

Mr McGregor replied: "It is not something I am aware of." Mr Cooper asked: "Are you aware that, at times, officers would arrive on duty and be handed firearms when they were drunk?" Mr McGregor: "No, I am not aware of that."

Mr McGregor also denied that officers would sell steroids or hardcore pornography, saying "Of these things you are saying now I knew nothing at all."

Mr Cooper suggested that officers in royalty protection sat on the thrones of the Queen and Prince Philip with their feet up, put their thumbs up in a comical pose and had their photographs taken. Mr Cooper rejoined: "That is just what you have done, isn't it?"

Mr McGregor replied: "No, I do not recall doing anything like that." He added: "I may have sat on one of the thrones, but I do not recall doing any comical poses."

Page denies five counts – two of fraudulent trading, one of intimidation, threatening to take revenge and making a threat to kill between January 1, 2003 and March 30, 2007.

The trial continues.