[2] In January 1958 she joined the Fishery Protection Squadron where she served until April 1963,[2] seeing service in the Cod Wars.

On 4 September 1960, ICGV Ægir, an Icelandic patrol vessel, attempted to take a British fishing trawler off the Westfjords.

Þór's captain, Eiríkur Kristófersson, said that he would not do so, and ordered his men to approach the trawler with the gun manned.

In response, Russell threatened to sink the Icelandic boat if it opened fire upon Hackness.

Following a refit at Rosyth she joined the 20th Frigate Squadron based at Londonderry Port.