Although HMS Jason had been designed as a minesweeper, in September 1939, she was converted into an antisubmarine vessel and assigned to 1st Anti-submarine striking force at Belfast.

After the repairs, she was again deployed to convoy defence, this time in the North West Approaches, during which she came under repeated attack from German U-boats U-32 and U-28.

After one month in that role, yet more repairs were needed after a collision with the rescue tug Scheldt, in which significant structural damage to her stem was sustained.

This was part of the most vicious U-boat attacks of the war, with ten ships being lost from Convoy HX 79 alone.

Part of the re-fit was in preparation for her new assignment, which was to operate in Arctic waters with ships of the Soviet Union.

Heavy seas made visual communication almost impossible, and Jason was damaged by the weather and forced to carry out repairs to the ventilation trunking.

The weather started to clear on 23 February, but German aircraft sighted the convoy and one day later it was attacked by U-255 and U-622.

Throughout this period, they were under constant air attack, but neither suffered any significant damage (two bombs hit HMS Britomart and skidded along the deck, but neither exploded).

It was noted that standards of the crew had dropped significantly since operation in Soviet waters, but both ships performed so well that the Russians offered to buy them.

On completion of the re-fit she was nominated to join the newly formed 1st Minesweeping Flotilla, along with HMS Britomart, Gleaner, Halcyon, Harrier, Hussar, Salamander, Seagull and Speedwell.

Throughout February and March they carried out their duties in the North Sea, and were subsequently nominated for a support rôle during the Normandy Landings.

On 18 June, she was involved in a collision which caused significant damage and flooding and so she was required to retire to Portsmouth for repairs.

They were now operating out of Mulberry Harbour at Arromanches, with instructions to keep the channel between there and Portsmouth clear of mines.

On 22 August they were sent to clear a magnetic minefield off Cap d'Antifer in preparation for HMS Warspite, Erebus and Roberts to move in and bombard enemy positions at Le Havre.

"It is felt that the fury and ferocity of concerted attacks by a number of Typhoon aircraft armed with rockets and cannons is an ordeal that has to be endured to be truly appreciated."

In January 1945, the 1st Minesweeping Flotilla was reassigned to Harwich to counter mining efforts by German E-boats and midget submarines.

It was one task that was not completed as soon as VE-Day dawned and she continued in this capacity until a serious collision in the North Sea with HMS Hazard caused serious structural damage, forcing a return to Portsmouth for repairs.