The British government is looking at updating treason laws so that it can prosecute ISIS fighters returning from Syria and Iraq.
Plans include redefining the word “enemy” so that it covers terrorist groups as well as nations, and widening the legal definition of “acts of betrayal”.
Another proposal on the table is requiring people with a legitimate reason to travel, perhaps aid workers, to justify their decision to visit dangerous hotspots.
Counterterrorism police on Wednesday arrested a 37-year-old Briton at the Channel Tunnel terminal in France, who was thought to be returning from fighting in Syria.
The Home Office said the review was in progress and no conclusions have been reached.
"We make no apology for doing whatever is necessary to keep the UK safe from those who pose a threat," a government spokesman told The National.
“The individuals who remain in the conflict zone include incredibly dangerous individuals, many choosing to stay to fight or otherwise support [ISIS]. They turned their back on this country to support a group that butchered and beheaded innocent civilians, including British citizens.
“The UK already has a range of tools to manage the threat posed by those who travelled to take part in the conflict such as Temporary Exclusion Orders, and we are determined where possible to prosecute those involved in atrocities.”
The reforms are aimed at increasing the number of prosecutions of British citizens on their return to the UK and to also toughen the sentences.
The government fears it is incredibly hard to successfully prosecute returning fighters but also wants to allow some legitimate travel.
About 900 British citizens have been deemed a national security concern after travelling to Syria and Iraq, Home Office figures show.
About 200 are thought to have been killed and about 300 alive and still in the Middle East.
Of the roughly 400 back in the UK only 10 per cent - or 40 - have been prosecuted.
“We need tough sanctions for betrayal. We can’t wash our hands of those who spread terror abroad but can only deal with them if we’re willing to act and prosecute those who have betrayed our communities,” said Tom Tugendhat, the Conservative chairman of the foreign affairs committee.
The man arrested on Wednesday at the port of Coquelles was in a zone where British officials have the right to question people planning to travel to the UK.
He was held on suspicion of preparing for terrorist acts and membership of a proscribed organisation. A warrant obtained on Thursday could keep him in custody without charge until Tuesday.
The treason changes are expected to be part of a wider bill to counter hostile state activity, including the prosecution of foreign spies who operate in the UK.
