Brexit: Britons undermining the country through 'extreme EU loyalty' must be tried for treason, says Tory MEP

British people undermining the country through “extreme EU loyalty” must be tried for treason, a Tory MEP says.

David Campbell Bannerman has been accused of “putting the knife into free speech” after demanding the revival of an archaic law to prosecute strong allegiance to the EU.

“It is about time we brought the Treason Act up to date and made it apply to those seeking to destroy or undermine the British state,” he tweeted.

“That means extreme jihadis. It also means those in future actively working undemocratically against U.K. through extreme EU loyalty.”

The extraordinary call was condemned by Virendra Sharma MP, a Labour MP and supporter of the anti-Brexit Best for Britain, who said: “This c-list Tory MEP is suggesting putting the knife into free speech.

“David Campbell Bannerman should think long and hard about his spiteful populist rhetoric. This type of extremism is the real danger facing this country.”

Stephen Doughty, a Labour backer of the People’s Vote campaign, called on Theresa May to disown “such campaigns of political bullying”.

“If his aim is to intimidate those of us who support a People's Vote on a final Brexit deal into silence I can only tell him he will fail,” he added.

The MEP – who was elected under the Ukip banner, but defected to the Conservatives in 2011 – spoke out after a wider call to bring back the 1351 Treason Act.

Amber Rudd, the former home secretary, joined forces with police and spy chiefs to argue it was needed to prosecute returning jihadists.

It follows the revelation that Sajid Javid, Ms Rudd’s successor, will allow two of the notorious “Beatles” Isis fighters to face the death penalty in the United States.

The home office has insisted UK anti-terror laws are not strong enough to prosecute London-born Alexanda Kotey and El Shafee Elsheikh in this country.

The last person to be convicted under the Act was William Joyce, more commonly known as Lord Haw-Haw, who was hanged in 1946 for assisting Nazi Germany.

A report by the Policy Exchange think tank calls for a new law to “revive the law of treason and recognise that betrayal – treason – is a clear moral wrong”.

However, it would only be used for aiding “a state or organisation that is attacking the UK or preparing to attack the UK or against which UK forces are engaged in armed conflict”.

The report reads: “In most cases, people convicted of treason should be sentenced to life imprisonment, a sentence which reflects the gravity of the wrong of betrayal, deters others, and incapacitates the offender.”