Giving evidence to the same inquiry, Eliza Manningham-Buller revealed that there was such a surge of warnings of home-grown terrorist threats after the invasion of Iraq that MI5 asked for – and got – a 100 per cent increase in its budget. Baroness Manningham-Buller, who was director general of MI5 in 2002-07, told the Chilcot panel that MI5 started receiving a “substantially” higher volume of reports that young British Muslims being drawn to al-Qa’ida.

She told the inquiry: “Our involvement in Iraq radicalised, for want of a better word, a whole generation of young people – a few among a generation – who saw our involvement in Iraq and Afghanistan as being an attack on Islam.”

She added: “Arguably we gave Osama bin Laden his Iraqi jihad so that he was able to move into Iraq in a way that he was not before.”

Her words are in stark contrast to the claim that Mr Blair made in front of the same inquiry on 29 January. The former prime minister told Sir John Chilcot: “If I am asked whether I believe we are safer, more secure, that Iraq is better, that our own security is better, with Saddam and his two sons out of office and out of power, I believe indeed we are.