London (CNN) Britain's security services missed opportunities to prevent the terror attack that killed 22 people at an Ariana Grande concert in Manchester in May 2017, a parliamentary report concluded Thursday.

The report, which also examined the response to other terror attacks to hit the country in 2017, highlighted a litany of errors made by police and security services, including MI5's decision not to place travel restrictions or monitoring on Abedi, meaning he was able to return to Britain from Libya to carry out the attack.

"What we can say is that there were a number of failures in the handling of Salman Abedi's case and while it is impossible to say whether these would have prevented the devastating attack, we have concluded that, as a result of the failings, potential opportunities to prevent it were," ISC chairman Dominic Grieve said in a statement.

A woman appears emotional as she looks at flowers left in St. Ann Square on Tuesday, May 23, 2017, in Manchester, England.

The findings of the report make grim reading for the security services. It found that:

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