He returned to the United Kingdom on the outbreak of the First World War, and after initially being rejected due to poor eyesight, he enlisted in the Royal Naval Volunteer Reserve in 1916.

Undeterred, Bourke returned to England, at his own expense, where he successfully joined the Royal Naval Volunteer Reserve, serving on motor launches.

During action on the night of 23 April, Bourke's launch picked up 38 sailors from the blockship HMS Brilliant and towed the crippled ML 532 out of the harbour.

After searching and finding no one, he withdrew, but hearing cries from the water he turned back, found an officer and two seamen clinging to an up-turned boat, and rescued them.

Bourke is buried in section O, plot 10, grave 16 in Royal Oak Burial Park, Falaise Drive, Victoria, British Columbia.

HMCS Malahat, Victoria's Naval Reserve Division, honours Bourke at his gravesite in Royal Oak Burial Park with a graveside ceremony each Remembrance Day.