This is the story of the 20th Minelaying Flotilla in WW1 and WW2. During the early years of WW1 the existing minelaying vessels in service with the Royal Navy were found to be far too slow to penetrate into the strategically important waters around Holland, Denmark, Germany and Sweden under the cover of darkness and survive. As a result, a flotilla of fast destroyers was created that could be readily converted from their normal role into minelayers. Many of the guns and torpedo tubes could be quickly embarked and mine-rails, mines and sinkers fitted in their place. These specialized ships were then dispatched deep into enemy waters. As the war progressed they caused increasing havoc amongst enemy shipping but also suffered greatly as a result of their endeavors.Between the wars a new minelaying class was built with dual capability. They were soon called into action at the outset of WW2 and laid minefields around Norway, Germany and occupied Europe. Full details of the operational history of the flotilla with details of the mines used and the special adaptations required to be fitted to destroyers, plus first-hand accounts from crew and officers who served on them are also covered.