Unlike many so-called sister ships Harlesden and Harpalion were identical except for a minute difference in tonnage. Built alongside each other in the yards of Hawthorn, Leslie & Co. at Hebburn-on-Tyne, Newcastle, they were completed in 1932 and delivered to their new owners J. & C. Harrison Ltd. for immediate service. Registered at 5,483 and 5,486 tons fross respectively, each measured 427½ feet in length with a 56¼ foot beam and was driven by a single screw powered by engines from the North East Marine Engineering Co. of Newcastle. Both proved reliable additions to the Harrison fleet although neither survived the Second World War when their value was even more appreciated.

Harlesdon was on passage from Hull to New York in ballast when she was bombed by German aircraft on 22nd February 1941 about 500 miles E.S.E. of Cape Race. Later the same day she was shelled and sunk by the German battlecruiser Gneisnau, from where the aircraft were presumed to have come. Seven crewmen were killed but the master and thirty-three others were picked up and became prisoners-of-war.

Harpalion,carrying 600 tons of mineral ores, was one of sixteen merchantmen comprising Convoy QP.10 which left Murmansk bound for Reykjavik on 10th April 1942. Depite a heavy escort, the convoy was subjected to frequent air and submarine attacks and early on 13th April, Harpalion was bombed and so severely damaged that she was sunk by gunfire from one of the escorting destroyers. Fortunately her entire crew, together with eighteen survivors from the New Westminster City, were all saved