HMS Unicorn (S43): The Last Boat Built at Cammell Laird for Sixteen Years

Built at Birkenhead

HMS Unicorn was laid down at Cammell Laird's Birkenhead yard on 13 March 1990, launched on 16 April 1992 and commissioned into the Royal Navy on 25 June 1993, an Upholder-class diesel-electric submarine.

She holds a distinctive place in shipbuilding history: she was the last vessel built at Cammell Laird until construction began on HMS Queen Elizabeth in June 2010, a gap of nearly seventeen years for one of Britain's most storied shipyards.

A Brief Royal Navy Career

Unicorn's operational service took her across the Mediterranean, east of Suez, the Gulf of Oman, and the Indian and Persian Gulfs, but her time in Royal Navy colours proved remarkably short.

Caught up in the post-Cold War defence cuts that saw the entire Upholder class judged surplus to requirements, she was decommissioned at Devonport on 16 October 1994 after barely sixteen months of active service, a truly abrupt end for a submarine that had only just entered the fleet.

A Second Life in Canada

The British government offered Unicorn and her three sister boats to Canada in 1993, an offer finally accepted in 1998 under an arrangement that saw the four submarines leased to Canada for US$427 million, with provision for eventual sale at minimal further cost.

Delays caused by problems with piping welds slowed her reactivation, but Unicorn was formally handed over to the Canadian Forces on 6 August 2001, arriving in Canada on 19 October, and was finally commissioned as HMCS Windsor on 4 October 2003, beginning a new chapter in Royal Canadian Navy service under a new name and a new flag.