The Vickers Vigilant was a British 1960s era MCLOS wire-guided anti-tank missile used by the British Army. It was also licence-built in the United States by Clevite for the US Marine Corps, and sometimes known as Clevite rounds in this case.

Development began at Vickers-Armstrongs' in 1956 as a private project in order to prevent the company's Weybridge Guided Missile Department having nothing to do after the cancellation of Red Dean. By 1960 it had completed development and an extensive testing program, but the War Office remained disinterested as they wished for the Department to be disbanded as part of the ongoing formation of British Aircraft Corporation. On several occasions the Office explicitly stated they did not want to provide any encouragement to the team as this might make it harder to close the division down in the future.

After considerable debate spanning several years, the project eventually won an initial order as it was the only suitable design to quickly arm the Ferret armoured car. By this time the War Office had already decided that their ultimate weapon for this role would be the Swingfire. An order for several thousand Vigilant was placed late in 1961 as an "interim weapon" whilst awaiting Swingfire. The order immediately resulted in several additional orders from Kuwait, Saudi Arabia, Libya and Abu Dhabi, along with Vigilant-armed Ferret sales to the UAE and Yemen. The order also sealed the US decision to license Vigilant for local production.

Swingfire did not arrive until 1969, and during that time the medium-range man portable version had been dropped. This left the Vigilant in use with the infantry and airborne forces well into the 1970s. Approximately 18,000 were produced in total.