Hate preachers will be banned from entering mosques and universities under plans by Theresa May to ensure Anjem Choudary's radicalisation of young Britons can never be repeated.

Ministers are looking at whether they can order blanket bans to stop extremists addressing large groups in public as an additional measure to clamp down on radicalisation.

The government is also considering what more can be done to force social media sites to take down extremist messages and videos posted online.

The changes go further than anything brought into law by David Cameron and could form the centrepiece of a new Extremism Bill due to be placed before Parliament by May.