The ST Leukos was an Irish commercial trawler that was sunk off the north coast of Ireland by a German U-boat on 9 March 1940.

The vessel, which had been fishing in the company of British trawlers, was attacked by the German submarine U-38 off Tory Island.

First the Leukos had positioned herself between the fleeing British trawlers in the hope that the U-boat would respect Irish Neutrality.

This is the view taken by the Irish Seamen's Relatives Association which holds that the Leukos attempted to ram the U-38 as it threatened the British fishing fleet.

She called to Troon, Scotland for coaling and then headed for 'the bank', a fishing ground, north-west of Tory Island.

On 21 March her empty lifeboat was found off Scarinish on the Island of Tiree in the Scottish Inner Hebrides.

There were theories: was she on a target list because of her previous role as a boom defence vessel; or was there a structural weakness caused by her collision with ST Thomas Bartlett?

His sources were former U-boat personnel and recently declassified intelligence resulting from decryption of encrypted German radio communications, known as ‘Ultra’.

(Seddock might have also been armed) On 11 September 1939, U-38, on its first patrol, shelled and sunk the Irish-flagged oil tanker Inverliffey[2] carrying 13,000 tons of gasolene.

Stewart, which transferred them to the American freighter SS City of Joliet and landed at Antwerp, Belgium.

[9] On its fifth patrol the U-38 landed Walter Simon, alias "Karl Anderson", a Nazi agent, at Dingle Bay in Ireland on the night of 12 June.

Not noticing grass overgrown on the rusting rail-tracks of the Tralee and Dingle Light Railway which had closed 14 months earlier, he asked "when is the next train?"