Proposals to prevent would-be jihadists coming back to the UK have been significantly watered down because they were unworkable, according to the Coalition's terror Tsar.

David Anderson said instead a system of "managed return" was contained in new counter terror laws set out yesterday.

The publication of the Bill came as two brothers became the first to be jailed for travelling to an extremist training camp in Syria.

Another British man taunted the Home Secretary by posing a picture on social media websites holding a gun in one hand and his newborn baby in another and claiming that the UK's "shoddy security system" had allowed him to reach Islamic State.

Mr Anderson, the Independent Reviewer of Terrorism Legislation, said that the new legislation was "nothing like as dramatic" as plans outlined by David Cameron earlier this year.

At that stage human rights groups protested that Mr Cameron's plans were illegal under international law and would leave UK citizens effectively stateless.

Mr Anderson told MPs and peers he believed that it had become clear such a move would "neither legally nor practically" work. The new Counter-terrorism and Security Bill does include new legislation that can ban insurance companies from paying for terrorist ransoms. After a climbdown by the Liberal Democrats, powers will be re-introduced to relocate terror suspects across the UK.

Certain organisations, such as colleges, universities, the police and probation providers, will also have an obligation to help deter radicalisation. Police will have new powers to force internet firms to hand over details that could help identify suspected terrorists and paedophiles, following criticism of Facebook over the murder of soldier Lee Rigby earlier this week. Police and border staff will also be given the power to seize the passports of suspects thought to be travelling abroad for terror purposes.

Last night Rachel Logan, from Amnesty International raised concerns over some of the new powers, saying it was "dangerous to rush through this grab-bag of measures without proper scrutiny or challenge".

"While the Government needs to ensure that anyone suspected of criminal activity is investigated, measures like invalidating passports and excluding British nationals from their home country push the boundaries of international law."