At the outbreak of the First World War in July 1914, Callaghan set sail in his flagship, the battleship HMS Iron Duke, for his war station at Scapa Flow.
There he met his successor-designate Sir John Jellicoe, who had received orders from First Lord of the Admiralty Winston Churchill to relieve the ageing Callaghan of command of his fleet.
Jellicoe had resisted the order, believing it would cause tension in the fleet, but the order was confirmed by the Admiralty and Jellicoe was instructed to carry it out.
Callaghan was bitterly disappointed not to command his fleet in the war he had completely readied it for.

In Autumn 1914 Callaghan took part in a Court of Inquiry into the conduct of Rear Admiral Ernest Troubridge for his failure to pursue the battlecruiser SMS Goeben and the light cruiser SMS Breslau.
He referred the matter to a court-martial which ultimately found the case against Troubridge not proven.

Callaghan was appointed First and Principal Naval Aide-de-Camp to the King on 11 September 1914 and became Commander-in-Chief, The Nore in January 1915.
He was advanced to Knight Grand Cross of the Order of the Bath on 3 June 1916 and was promoted to Admiral of the Fleet on 2 April 1917.

Callahan retired in March 1918 and became King of Arms of the Order of the Bath in May 1919.
He died at 11 Cadogan Court, Chelsea, London on 23 November 1920 and was given a funeral at Westminster Abbey, following which he was buried in the churchyard of St Mary the Virgin at Bathwick, Somerset.
At the outbreak of the First World War in July 1914, Callaghan set sail in his flagship, the battleship HMS Iron Duke, for his war station at Scapa Flow. There he met his successor-designate Sir John Jellicoe, who had received orders from First Lord of the Admiralty Winston Churchill to relieve the ageing Callaghan of command of his fleet. Jellicoe had resisted the order, believing it would cause tension in the fleet, but the order was confirmed by the Admiralty and Jellicoe was instructed to carry it out. Callaghan was bitterly disappointed not to command his fleet in the war he had completely readied it for.
In Autumn 1914 Callaghan took part in a Court of Inquiry into the conduct of Rear Admiral Ernest Troubridge for his failure to pursue the battlecruiser SMS Goeben and the light cruiser SMS Breslau. He referred the matter to a court-martial which ultimately found the case against Troubridge not proven.
Callaghan was appointed First and Principal Naval Aide-de-Camp to the King on 11 September 1914 and became Commander-in-Chief, The Nore in January 1915. He was advanced to Knight Grand Cross of the Order of the Bath on 3 June 1916 and was promoted to Admiral of the Fleet on 2 April 1917.
Callahan retired in March 1918 and became King of Arms of the Order of the Bath in May 1919. He died at 11 Cadogan Court, Chelsea, London on 23 November 1920 and was given a funeral at Westminster Abbey, following which he was buried in the churchyard of St Mary the Virgin at Bathwick, Somerset.
George Callaghan