Britain faces a level of terror threat not seen since the IRA bombings of the 1970s, according to a new watchdog.
Max Hill QC, the independent reviewer of terrorism laws, told the Sunday Telegraph that Islamist extremists were targeting UK cities.
He credited the effectiveness of the intelligence services in limiting the level of threat to Britain.
Home Secretary Amber Rudd told ITV's Peston on Sunday that defending the UK was her "main priority".
Ms Rudd said she agreed with Mr Hill's assessment of the current terror threat facing the UK, adding that ensuring a country is well-defended is "the most important job a home secretary does".
Mr Hill also pledged to review anti-terror measures over concerns about any infringements of freedom.
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Mr Hill, who successfully prosecuted the failed 21/7 bombers and the killers of Damilola Taylor, said the so-called Islamic State was planning "indiscriminate attacks on innocent civilians of whatever race or colour" in UK cities, close to the scale of Provisional IRA attacks of the 1970s.