The system which gives barristers security clearance to represent the interests of terror suspects at secret court hearings is "critically flawed" and must be reformed urgently, MPs said on Sunday.

The "special advocates" are cleared to see secret documents from the intelligence services, but are not allowed to speak to the suspect or their lawyers once they have seen this information.

The advocates say the rule makes it impossible for them to represent the suspects properly because they are unable to put allegations to them and find out whether there is an innocent explanation.

The all-party constitutional affairs committee have called on ministers to urgently review the way the system operates.