"Norfolk" was first commissioned on 7 March 1970 and was present at Portsmouth Navy Days. In 1972 "Norfolk" began a refit to replace 'B' turret with four Exocet launchers. She was thus the first Royal Navy warship to be armed with the Exocet missile system. She also became the first warship to carry three independent missile systems: Exocet, Sea Cat and Sea Slug. "Norfolk" recommissioned in 1974. She had a displacement of 5,450 tons and was quite a large ship, considering she was classified as a destroyer. She undertook numerous deployments to the Indian Ocean, Mediterranean Sea and South Pacific Ocean. By the mid-1970s it was clear that the Mk 2 Sea Slug did not represent a significant improvement over the earlier version, because it was even less reliable and attempts to develop successful sustainer motors had failed. There was only money to fit new computer command and control to the three other second group County class, so Norfolk was reduced to increasingly marginal and third line roles.