David Perry, 66, pleaded guilty to charges of sending grossly offensive communications and indecent communications to the deputy Labour leader in May last year.

Perry referenced the Mail on Sunday article in an email sent 10 days after the paper reported that Tory MPs had accused her of crossing and uncrossing her legs to distract Mr Johnson during Prime Minister's Questions.

Condemned by Ms Rayner - who described it as "disgusting" and "completely untrue" - the story prompted a huge backlash when it was published.

In an email described as "vile and abusive" by prosecutors sent to the Ashton-under-Lyne MP's constituency office, Perry made "crude and offensive references" to her appearance and accused her of being a "puppet of the industrial military complex".

"Please get off the news channels and go get a job in a fish factory," he wrote.

Perry was arrested by Greater Manchester Police in July last year but was only charged after Ms Rayner requested a Victim's Right to Review (VRR) the initial Crown Prosecution Service (CPS) decision not to prosecute.

In a victim personal statement, she said she was "appalled at the level of repugnant malice" directed towards her and questioned why anyone would think it was acceptable to send such offensive words to a woman.

Perry, of Weybridge, Surrey, initially claimed his email account had been hacked, before admitting the charges.

He will be sentenced on 16 November at Staines Magistrates' Court.

Rosemary Ainslie, head of the CPS Special Crime Division, said: "Perry's email was highly offensive and insulting to Ms Rayner, and his comments have no place in a civilised society.

"Neither she nor her constituency staff should have to be subjected to such vitriol - it is completely unacceptable.

"The public should know that they cannot simply send such grossly offensive communications without repercussions. Online communications can be traced and people breaking the law will be brought to justice."