It is understood the two people suspected of carrying out the knife attack were known to Britain's domestic security service.

CNN: SHARE THIS

Lawyers for Brown based part of their appeal on a claim that he was unaware a knife attack was to be carried out.

BBC: Thomas Devlin murder convictions appeal fails

Sir Declan, who heard the case with Lord Justices Higgins and Girvan, stressed the impact of the knife attack on Thomas's parents and the boys who survived it.

BBC: Thomas Devlin murderer gets reduced tariff