HMS Seagull was a Halcyon-class minesweeper, and the first all-welded Royal Navy ship, built entirely without rivets.

This gave a substantial improvement in costs and build time, the comparison being the half-sister ship built using rivetted construction on another slipway in the same dockyard.

[1] She was adopted by the civil community of Christchurch, Hampshire after a successful Warship Week National Savings campaign in February 1942 During the Second World War she helped escort 21 Arctic convoys, and participated in Operation Neptune.

She was also involved in the accidental sinking of the Polish submarine ORP Jastrząb, along with HNoMS St Albans, during the passage of Arctic Convoy PQ 15.

A court of Enquiry found that Jastrząb was 100 nmi (190 km; 120 mi) out of position, in an area where U-boats were expected to operate, and no blame could be attached to either commander.