A beautiful RN badge, the larger of the two sizes of pentagon boat badges, this one is from WW2 Minelayer HMS Apollo.

HMS Apollo (M01) was an Abdiel-class minelayer built for the Royal Navy during World War II. Commissioned in 1943, she combined high speed with heavy mine capacity, laying minefields in the English Channel and North Sea to disrupt German shipping. Apollo also transported troops and supplies, notably supporting Allied operations in Europe. After the war, she served in various roles, including training and transport, and took part in post-war deployments. The ship was decommissioned in 1961 and later scrapped, having had a versatile and active naval career.