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The ex-head of MI5 warns the there is a "very serious terrorist problem" in the country.
MI5 has admitted for the first time that it made a mistake in failing to track the 2017 Manchester Arena bomber, MPs have said.
A report by the Intelligence and Security Committee said MI5 recognised it had moved "too slowly" to establish how dangerous sucide bomber Salman Abedi, 22, really was.
The security service had cause to monitor Abedi's return to the UK from Libya days before the attack, the report said.
Twenty-two people died in the attack on 22 May 2018 after an Ariana Grande concert.