Martin McGuinness said republicans saw Scotland as Celtic cousins, a new book claims

Irish republicans refused to bomb Scotland because it is a “Celtic nation” with a similar history of English oppression, according to a British spy who infiltrated Sinn Fein.

Martin McGuinness, the former IRA commander, said Scotland was spared from the bombing campaigns in the last century because its language and culture were also suppressed by English rulers, according to Willie Carlin, an MI5 agent who infiltrated Sinn Fein.

In his new book, Thatcher’s Spy: My Life As An MI5 Agent Inside Sinn Fein, Mr Carlin recounts a conversation at the height of the troubles with Mr McGuinness, who went on to become deputy first minister in the Irish Assembly following the IRA ceasefire.

Mr Carlin said: “On the way back from Derry, [Martin McGuinness] made