Leaking valves in the veins of the legs causes veins to become large and bloated. These swollen veins are called "varicose veins" and are a very common problem, affecting more than a third of all adults in the UK. Varicose veins reduce people's quality of life by causing problems such as pain, itching and restless legs. Varicose veins may also damage the skin over time causing problems such as bleeding, skin colour changes, eczema and even break-down in the skin which is called an ulcer. Newer, "key-hole" methods of treating leaky veins have been developed as an alternative to surgery and can be performed under local anaesthetic with the patient awake. Rather than cuts in the skin, these minimally invasive techniques are performed through tiny stab wounds; little larger than needle holes. The varicose vein is then destroyed from within, usually using heat to burn the inside of the vein. These procedures are popular; with a rapid recovery and a very high success rate. However these methods also require the vein to be surrounded by a large volume of dilute local anaesthetic which can to be slightly painful to administer. A technique called "Foam sclerotherapy" involves the injection of a drug which has been mixed into a foam. This goes into the vein and causes it to stick shut. This procedure is near painless to perform as very few, small local anaesthetic injections are required; however the chance for a successful treatment first time are lower and patients may need to return for repeat treatments to successfully treat the vein.