British spies were told by Canadian intelligence within 48hours that Isis bride Shamima Begum had been smuggled over the Syrian border with her two friends, sources have alleged.
The Globe and Mail in Canada cited two sources who confirmed that the Canadian Security Intelligence Services had passed the information on to MI5 and MI6.
The newspaper said that British intelligence agencies were made aware within the next two days, raising the likelihood that they knew before Scotland Yard.
It follows the revelations by journalist Richard Kerbaj in his book 'The Secret History of the Five Eyes' that the Bethnal Green school girl was trafficked into Syria by a double agent - on the paroll of both ISIS and Canadian intelligence.
The book continues that Canada finally admitted its involvement in the plot as bosses feared becoming exposed, then also managed to convince Britain to cover-up its role.
The revelations will likely fuel calls for an investigation into the British school girl - who is currently in a camp in north-west Syria has made multiple attempts to restore her British citizenship, however she most recently failed in her Supreme Court bid to return to the UK.
The Supreme Court ruled on national security grounds that she cannot return to Britain to pursue an appeal against the decision.
The law states a person's citizenship can be stripped if they are deemed to be in the public interest.