A commemoration dinner to be held for James Magennis, VC, by the Northern Ireland branch of the Submarine Association on August 2 will recall his part in one of the most daring submarine attacks of the Second World War.

The sinking of the 10,000-ton Japanese cruiser Takao in the Johore Strait between Singapore Island and the mainland by the 30-ton midget submarine XE3 on July 31, 1945, required intricate pilotage and, after that, great courage and determination from the submarine’s diver. Her CO, Lieutenant Ian Fraser, had to take his tiny and slow craft through 40 miles of minefields and hydrophone listening posts, which were continually patrolled by surface vessels — not to mention an anti-submarine boom through which, thanks to a Japanese oversight, XE3 was able to slip undetected.

Once these hazards had been negotiated, Fraser manoeuvred XE3 under the cruiser’s midships section. It was now Leading Seaman Magennis’s dangerous task, as the submarine’s diver, to exit through XE3’s “wet and dry” hatch and attach limpet mines to the cruiser’s hull which, as the tide fell, sank down on to the midget submarine in the shallow harbour, threatening to crush her. The mines were intended to cling by magnets. But Takao’s steel plates were so barnacle-encrusted that Magennis had to chisel and scrape a bare patch for each of them before he could get the magnets to work.

After half an hour of struggle in nightmare conditions, with his breathing apparatus malfunctioning and his hands lacerated and bleeding from scraping against the barnacles, Magennis managed to attach the limpets and regained XE3 in a state of near-collapse.

The limpet mines were to be augmented by the powerful blast of the two two-ton charges that XE3 carried on the port and starboard sides of her hull. These were meant to be released by a mechanism inside the submarine. But this malfunctioned and only the port side charge fell away. Exhausted though he was, Magennis volunteered to go outside the XE3 once more with his faulty apparatus, and release the recalcitrant charge with a spanner. After seven more tense minutes, with the time fuses ticking away, he was successful and the charge dropped clear.

At 9.30 that evening, with XE3 having extricated herself with great difficulty from beneath the hull of Takao and made her escape from the area, the charges and limpet mines detonated, tearing a 60ft-long rent in the cruiser’s hull, completely immobilising her and settling her on the bottom of the harbour. Both Magennis and Fraser were awarded the Victoria Cross for this exploit.

For many years after his death in 1986 there was no memorial to Magennis, a Roman Catholic, in his native Unionist-ruled Belfast. He was also, as a British war hero, an embarrassment to the nationalist community.

At that time, it fell to Bradford, where he moved and worked as an electrician for 30 years, to put up a plaque to him. Amends were made in 1999 when a handsome 6ft-high Portland stone and bronze monument was unveiled in the grounds of Belfast city hall.

XE3’s former CO, Commander Ian Fraser, VC, and members of James Magennis’s family, will be attending the August 2 dinner in Belfast. Other ex-submariners, former naval personnel and members of their families who wish to attend are invited to contact the chairman of the Northern Ireland branch of the Submarine Association, Douglas Erskine, on 028-9065 7591 or 07715 368918.