Since taking over as Defence Secretary, Gavin Williamson has prided himself on the robust stance he has adopted towards Vladimir Putin’s Russia.

But now he risks flushing his reputation as a statesman down the pan in his battle with the Kremlin after visitors spotted a roll of lavatory paper adorned with Mr Putin’s face in his MoD office. Under the president’s image, Russian letters spell out a highly offensive insult.

The move is unlikely to amuse Moscow, which has been locked in a war of words with Mr Williamson since the Novichok poisonings in Salisbury last year. At the time, Mr Williamson attracted widespread mockery by limply saying that Russia should ‘go away and shut up’.

Lavatory humour: Putin loo roll is pictured at a bathroom in Ukraine

And last week he warned the East not to ‘mess with’ Britain, after declaring that the RAF’s new fleet of F-35B Lightning II stealth jets were operational.

Similar products have been on sale in Crimea –- which Russia annexed from Ukraine in 2014 –- and brandished by members of the region’s non-Russian minority.

Mr Williamson, a former Chief Whip, has caused consternation in Westminster before with his idiosyncratic behaviour. He used to keep a tarantula called Cronus in his whip’s office – but it was barred from moving to the MoD because a member of his staff has arachnophobia.

Last month, The Mail on Sunday revealed that Mr Williamson had been overheard plotting a Tory leadership bid in The Colony Grill in London’s Mayfair.

Party sources said that they had heard him boasting about his links with the DUP and how he could outmanoeuvre Jeremy Hunt and Sajid Javid at the next contest.

And last year this newspaper revealed that Mr Williamson had boasted he would ‘break’ Theresa May if she did not boost funding for the Armed Forces. His battles with Philip Hammond’s Treasury over the issue led to the Chancellor’s friends dubbing him ‘Private Pike’.

Laughing it off: Mr Williamson is said to have a good sense of humour and the toilet paper was 'a gift in jest' but the Kremlin refused to be drawn on the claim

Announcing the F-35Bs last week, Mr Williamson said that it would send a strong message to Russia: ‘It means don’t mess with us, because we have the capability and we have the people, and we have the will to always defend ourselves.’

A source close to the Defence Secretary confirmed that the Putin toilet roll was in his private office at the MoD, and said that Mr Williamson had acquired it as a light-hearted present from someone. They added: ‘It was a gift in jest. Everyone knows that Gavin has a very good sense of humour.’

A Kremlin spokesman did not respond to a request for comment.