Formed in 1968 & the 2nd pattern cap badge, the 1st pattern being Admiralty Fire Service which this badge is also known, The Admiralty Fire Prevention Service, it continued until 1991 when the Defence Fire Service was formed amalgamating all the previous military fire brigades such as The Army Fire Service which was formed originally in the 1940’s under the Pioneer Corps & continued its role under the Royal Army Service Corps post war until 1961 when it became more civilianised ! 
A fine cap badge & looks un issued due to condition & the slider cap attachment to the rear appears never to have been on a cap. The enamel is also very good on a government issue home office star with the St Edwards crown above, the words “Fire Prevention Service” within the red enamel circlet surrounded by the wreath, the ADMIRALTY anchor in the centre of the badge !