During an attack on the Japanese cruiser Takao in Singapore, Magennis showed extraordinary valour and bravery by leaving the submarine for a second time in order to free some explosive charges that had got caught.

His commanding officer, Lieutenant Ian Edward Fraser, was also awarded the Victoria Cross for his actions during the operation.

He was from a working class Roman Catholic family and attended St Finian's Primary School on the Falls Road, Belfast.

[4] In July 1945, Magennis, as acting leading seaman, was serving as the diver on the midget submarine HMS XE3, under the command of Lieutenant Ian Edward Fraser, as part of Operation Struggle.

On completion, Magennis returned to XE3 for the second time, allowing the four-man midget submarine to make its escape out to open sea to meet the waiting Stygian.

XE1's commanding officer, Lieutenant John Elliott Smart, and Sub-Lieutenant Harold Edwin Harper, received the Distinguished Service Cross.

[7] The citation was published in a supplement to the London Gazette of 9 November:[7] Leading Seaman Magennis served as Diver in His Majesty's Midget Submarine XE-3 for her attack on 31 July 1945, on a Japanese cruiser of the Atago class.

Shortly after withdrawing Lieutenant Fraser endeavoured to jettison his limpet carriers, but one of these would not release itself and fall clear of the craft.

Despite his exhaustion, his oxygen leak and the fact that there was every probability of his being sighted, Magennis at once volunteered to leave the craft and free the carrier rather than allow a less experienced diver to undertake the job.

The money from the Shilling Fund was spent quickly by Magennis and his wife; she remarked: "We are simple people ... forced into the limelight.

For the last years of his life, he suffered from chronic ill health, before dying on 11 February 1986 of lung cancer hours before his heroism was honoured by the Royal Navy Philatelic Office with a first-day cover.

"[9] A wall mural commemorating James Magennis on the 60th anniversary of VJ day was unveiled on 16 September 2005 by Peter Robinson, the Democratic Unionist Party Member of Parliament representing East Belfast, including Tullycarnet.

His portrait in oils was painted by Belfast artist Robert Taylor Carson who described Magennis as 'the perfect model - patient, attentive and completely natural.'

The painting was purchased by Mr. Nevill McGeough Bond of the Argory, who then presented it to the Northern Ireland War Memorial Building Fund in 1946.

In attendance was Petty Officer Tommy "Nat" Gould, another submariner Victoria Cross recipient of the Second World War.

Magennis was profiled in the 2006 television docudrama Victoria Cross Heroes, which included archive footage, dramatisations of his actions and an interview with Lord Ashcroft about his VC.