John McDonnells comments follow Sir Richard Bransons tweets relating to Jeremy Corbyns claim that he could not find a seat on a Virgin train, forcing him to sit on the floor, in a video about re-nationalisation of the UKs rail services. The tweets contained pictures and video taken from CCTV on the train, apparently showing Corbyn and his team walking past a number of empty – although reserved – seats.

Branson, who owns Virgin Trains, tweeted an image from the CCTV footage with a link to the companys press release about the incident, which later became known as Traingate. In the tweet, Branson said: Mr Corbyn and team walked past empty unreserved seats then filmed claim train was ram packed.

McDonnell, who is a close ally of Corbyns, defended the Labour Party leader, who maintained he had been unable to find seats on the train until a staff member intervened later, was critical of Bransons involvement in the scandal.

In an article for the Sunday Mirror, he wrote that Branson was a tax exile who thinks he can try and intervene and undermine our democracy.

He added: The whole purpose of the honours system is undermined when the rich and the powerful can collect their gongs without giving anything back. Its even worse when tax exiles are given honours.

Referring to Bransons residence on Necker Island, which the multi-billionaire bought aged 28 in 1978, McDonnell wrote: It should be a simple choice for the mega-rich. Run off to tax exile if you want. But you leave your titles and your honours behind when you go.

McDonnell was not the only member of Corbyns team to criticise Branson, with the Labour leaders leadership campaign director, Sam Tarry, telling BBC today: The bigger story is that a tax exile of more than 10 years decides to lay into [Corbyn] on social media in a very public way.

Richard Branson is literally laughing all the way to the bank at the British taxpayers expense. In the last year, this chap has made some £53m directly from the taxpayer.

Not all agreed with McDonnells stance, however. Corbyns opponent in the Labour leadership election, Owen Smith, told LBC Radio that McDonnells suggestion, seems a bit much, to be honest. I think it was merely pointing out the reality that Jeremy didnt need to sit on the floor.

Corbyns video was posted as an increasingly hostile situation developed between Southern Rail and its customers. A summer of cancelled services, delays and strikes by the company have caused misery for commuters as its operators have failed to find agreement with trade union RMT.

The local economy was also said to have suffered as the summers usual tourists stayed away due to the disruption.