Manchester, UK - Survivors of the deadly terrorist attack at an Ariana Grande concert in Manchester have taken legal action after an investigation exposed security failings before the tragedy.

The survivors of the bombing that killed 22 people are demanding justice from the British domestic intelligence service MI5, which is accused of having missed a significant opportunity to prevent the attack in Manchester on May 22, 2017.

More than 250 survivors have joined forces for the class action lawsuit.

"As it is an ongoing legal matter, we are unable or provide any further details, or comment further, at this stage," a letter from the law firms handling the case said, per the New York Times.

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The intelligence agency is keeping a low profile on the case and has not yet commented on the suit.

An official investigation into the incident was only launched last year.

According to this, the attack, which left hundreds injured, could have been prevented if MI5 had correctly assessed information about the Islamist attacker and passed it on to the relevant investigating authorities in good time.

The investigation report acknowledged crucial errors in handling the situation, including communicating the security risk.