Cameron announces powers to target jihadists

British jihadists who go abroad to fight in places such as Syria and Iraq could be prevented from returning home, under tough new anti-terrorism laws announced by the Prime Minister.

The measures will be put forward in a parliamentary bill in January.

The government estimates that 500 Britons have joined the militant group, Islamic State.

In a speech to the Australian parliament in Canberra, David Cameron said extremism "must be confronted in all its forms" and outlined his plans to deal with it.