In health clubs dotted around the City, Krav Maga's popularity is booming as its no-holds-barred approach attracts more Londoners. The club, which has just gone international, becoming a part of Krav Maga Global in Netanya, Israel, is the biggest in the UK and is expanding at a pace. Until two weeks ago, the institute held 19 classes in London every week with a further six across the Home Counties. But it has experienced such strong demand that it has just added another three classes a week to its London roster, and, having opened in Hertfordshire in July, it is preparing to move into the well-heeled commuter belt of Cambridge and Kent next year.