Paris attacker visited London, Birmingham

LONDON: One of the Islamic State terrorists behind the deadly Paris attacks had visited London and Birmingham earlier this year, counter-terrorism officials have found.

He managed to enter the UK before slipping away again to continental Europe despite Britain's heightened terrorism alert, 'The Guardian' newspaper reported.

In both cities he met people suspected of having the intention and capability of plotting or assisting terrorist activity against the UK.

Months later he was part of the series of attacks in Paris on November 13 that killed 130 people and plunged France into its biggest national security crisis since World War II.

It is unclear how he got into the UK but the British-based suspects he visited are under investigation by MI5 and police counter-terrorism units, the newspaper reports.

The UK Home Office, the government department responsible for border security, declined to comment so far.

A total of 11 terrorists were behind the attacks on Paris, which were carried out three weeks ago.

British security officials reacted immediately after the Paris attacks to review security and plans to thwart terrorist attacks against the UK.

Scotland Yard was drafting plans on how to respond barely two hours after the Paris attacks had started.

Of the 11 Paris attackers, nine are dead and two are on the run.

Most victims died at the Bataclan concert hall, others in attacks on bars and restaurants, with attacks also staged by suicide bombers outside the Stade de France during a football match between France and Germany.

A special British police unit was put on standby for an emergency national mobilisation of officers as security chiefs and government considered taking the UK to its highest state of terrorist alert.

Security analysts have warned that after Paris, UK might be the next target of IS militants, who now have an added motive to attack the country since it joined air-strikes on IS strongholds in Syria.