Here’s a quote from the BBC News website:

The government is due to unveil a new plan to tackle the threat posed by the potential return to the UK of British Islamists who are currently fighting in Iraq or Syria.
The Conservatives want new laws to impose temporary bans on extremists re-entering the UK from foreign conflicts.
However, the Lib Dems have questioned the legality of such measures.

‘Questioned the legality’?

They are terrorists FFS – kick the bastards AND their families out of the country and send them to Syria/Iraq. And forget the temporary bit – strip them of any UK citizenship at the same time.

Meh.