The Prime Minister has unveiled a new raft of powers designed to counter the threat from Britons who have travelled abroad to fight alongside the Islamic State extremist group.

Human rights have accused the government of “dumping suspect citizens like toxic waste”, but Labour says the new measures don’t go far enough.

What’s new?

The big new idea is to stop people who travel to Syria and Iraq to fight from coming back to the UK unless they agree to a strict control regime.

Suspected jihadis will have their passports cancelled while they are abroad, which should effectively stop them flying back to Britain.

Couldn’t we already do this?

Yes. Theresa May can also cancel the passports of terror suspects under Royal Prerogative powers.

This stops short of revoking their British citizenship but is considered a useful tool to prevent would-be terrorists from travelling abroad in the first place.

It’s not entirely clear that today’s proposal goes any further than the power that already exists, but the Home Office has been criticised for increasingly using powers not set out in legislation or subject to the scrutiny of parliament.

Citizenship stripping

The Home Secretary already has powers to deprive people of their British citizenship if she considers it is “conducive to the public good”.

At least 27 people have had their citizenship revoked for that reason since 2006, the vast majority of them under the current government.

The big problem with these powers is that they can only be used against people who have dual citizenship or – after a recent change in the law – those who were born abroad but have become naturalised British citizens.

This is because the government has an obligation under human rights law not to render people “stateless”.

Only people who already have another nationality or have a good chance of becoming a national of another country can have their British citizenship revoked.

As things stand, human rights law makes it impossible for the government to strip most UK nationals of their citizenship, no matter what they have done.

The passport measure announced today could affect all kinds of citizens, and ministers think it doesn’t break the rules on making people stateless because it is temporary.

Individuals will be prevented from returning for two years. And they will have the option to come back if they agree to strict conditions: things like reporting to police, taking part in a de-radicalisation programme or being subject to a Terrorism Prevention and Investigation Measure (Tpim) order.

Nonetheless critics say the move will effectively render people stateless, and there are bound to be legal challenges.

What aren’t we doing?

A number of politicians have suggested going further than the prime minister went today.

The mayor of London, Boris Johnson, has called for a “swift and minor change” to the law so there is a “rebuttable presumption” that people travelling to conflict zones without notifying the authorities are involved in terrorism.

Critics warned that this would overturn the legal principle that you are innocent until proven guilty, and the idea has not found favour with the government.

Labour has called for the reintroduction of control orders, which the coalition scrapped in 2011 in favour of less restrictive Tpims.

The two coalition parties are apparently still negotiating on Conservative plans to toughen Tpims by introducing the power to make suspects relocate to different parts of the country.