Prime Minister Tony Blair and Cabinet colleagues were briefed by the new head of MI5 yesterday on the terror threat facing Britain.

Jonathan Evans delivered his briefing at the first meeting of the Government's new committee on security and terrorism.

The committee will meet monthly and brings together representatives of the intelligence agencies, police and other relevant Whitehall bodies.

Home Secretary John Reid, Foreign Secretary Margaret Beckett and Communities and Local Government Secretary Ruth Kelly were also at the meeting.

The committee was set up as part of the reorganisation of the Home Office, which will concentrate on security and policing while prisons and the criminal justice system are being hived off to the Department for Constitutional Affairs, to be renamed the Ministry of Justice.

The new system is intended to provide a faster, more streamlined approach to dealing with terrorism and other security threats.

The new ministerial committee is supported by a new Office for Security and Counterterrorism (OSC), meeting weekly under the chairmanship of the Home Secretary.

Mr Blair's official spokesman said: "Today's meeting received an assessment of the current threat from the new director general of the security service (MI5) and agreed a programme to look at international terrorism and linkages to the UK, as well as the struggle for values and ideas.

"It's a recognition of the seriousness of the threat."