Brothers Gary and Martin Kemp delve into the violent history of gangland Britain and explore the country's most notorious crime families. They brothers begin their journey in Glasgow, the former murder capital of Europe and home to the gruesome torture method known as the Glasgow Smile, exploring the city where gang violence has a history littered with blade attacks. Written by CrimeSeries Fan

Brothers Gary and Martin Kemp turn their attentions to Britain's capital. London has always had criminals. The biggest city in Britain is like a magnet to those wanting to make a bob or two - even if that means taking the law into their own hands. Since the 1900's as many as 70 gangs have fought it out on London streets. The Second World War put pay to many of them but there was one vicious East End gang that kept alive even up to the 1960's though their origins went right back to the 19th century. Gary investigates the infamous Watney Streeters gang. A hundred years later a new wave of Asian immigrants had arrived in London. To protect themselves they formed gangs but it wasn't long before protection turned instead to extortion and then massive drug smuggling. Martin looks into the ruthless and dreaded Toot Nung gang from Southall, West London. Written by CrimeSeries Fan

In 2008, an illicit message sent from prison ignites a gang feud in Sheffield and a supposed traitor becomes a marked man. The gang is called the S3 - named after the postcode of their area. Violently territorial the S3 are at war with the rival S4 gang and become locked in a bloody vendetta. By 2009, police had a dossier listing 40 occasions on which the two gangs had opened fire on each other. Over 80 years earlier in the 1920's Sheffield was known as Little Chicago. A gambling gang's brutal beating leaves a man dead and a community reeling as violence tears through the streets of Sheffield. A murder so shocking the police take unprecedented steps and call in a gangbuster. Brothers Gary and Martin Kemp investigate two very different brutal Sheffield gangs, one old and one new, and explore how they have changed and evolved. Written by CrimeSeries Fan