It quickly emerged after Wednesday's Charlie Hebdo shootings that the prime suspects, brothers Cherif and Said Kouachi, had a long history of involvement in extremist circles.

The men are thought to have carried out the killings of 12 people in Paris. Both are thought to have died after a hostage siege in the town of Dammartin-en-Goele in northern France.

Cherif was arrested in 2005 while preparing to travel to Iraq to fight for an Islamist cell. He served 18 months of a three-year sentence.

Reuters has quoted US and European sources as saying that Said trained with al-Qaeda in the Arabian Peninsula in Yemen in 2011.

US government sources said both were listed in two American security databases including a "no fly" list.

Both men are also understood to have been on a a British watch and no-fly list, preventing them from entering the UK or passing through a British airport.

France's intelligence agencies are now likely to face the same questions asked of their UK counterparts after it emerged that the men who murdered Fusilier Lee Riby in Woolwich in 2013, Michael Adebolajo and Michael Adebowale, had featured in seven intelligence investigations.

In Australia the government has ordered an inquiry into Man Haron Monis, who died following a hostage siege in a Sydney cafe last month, after it emerged he had dropped off security watch lists.

Andrew Parker, the director general of MI5, said in a speech yesterday that the UK authorities have stopped three deadly terror plots in recent months, with terror-related arrests up 35 per cent compared with four years ago.

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Can any security service stop terror attacks?