Commander Geoffrey Mainwaring Sladen (3 August 1904 – 4 October 1985) was a Royal Navy officer and England international rugby union player.

Born in Reigate, Sladen attended Royal Naval College in Osborne and Dartmouth after finishing school.

He played rugby in the navy and was capped three times for England in the 1929 Five Nations as a centre three-quarter.

His submarine torpedoed the German cruiser Prinz Eugen off the Norwegian coast in 1942 and it had to be towed back to Germany for repairs due to a damaged stern.

[3] It was later revealed that for several weeks the HMS Trident had on board a reindeer, which had been gifted by the Soviets and was being transported to London Zoo.