The Labour leaders past and present were joined by colleagues including Mr Blair's fellow ex-PM Gordon Brown, current shadow chancellor Rachel Reeves and Ed Miliband at St Mary's Episcopal Cathedral.

Ruth Davidson, former leader of the Scottish Conservative Party, and former Tory chancellor George Osborne were also seen making their way into the cathedral.

Rowling wasn't the only famous face from the literary world present either, as Scottish crime writer Ian Rankin paid his respects.

Broadcaster Andrew Marr was seen taking a seat shortly before the service too.

Mr Darling died on 30 November, aged 70, after a stay in hospital where he was being treated for cancer.

The service followed a private cremation, which took place on Monday.

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Piper Finlay MacDonald provided music before the service began and a choir then sang hymns In The Bleak Midwinter, Love Divine and Jerusalem.

Shadow chancellor Ms Reeves delivered one of the eulogies, and others were read by Mr Darling's children, Anna and Calum, and his friend and former Labour minister Brian Wilson.

Mr Darling served as a Labour MP between 1987 and 2015. He was chancellor during the turbulent 2008 financial crisis and widely credited for his "calmness in a crisis".

Former prime minister Mr Brown described him as a "statesman of unimpeachable integrity whose life was defined by a strong sense of social justice".

He added: "I, like many, relied on his wisdom, calmness in a crisis and his humour."

Mr Darling's death prompted tributes from across the political spectrum, with First Minister Humza Yousaf describing him as a "giant" of Scottish politics.

Mr Darling is survived by his wife, Maggie and his two children.