The Severnside derby (Welsh: darbi Glannau Hafren) is a local derby in football in the United Kingdom between Welsh club Cardiff City and either of the English clubs, Bristol City or Bristol Rovers.

Due to the fierce rivalry and the history of the two teams the encounters can end up with some sort of conflict, commonly pre-organised.

While this has been mildly successful in stopping organised fights, fans still attempt to attack each other by throwing objects such as bottles and coins during the game.

In the programme a reporter wearing a hidden camera infiltrated the Soul Crew, exposing the use of racist chanting and abuse as well as a lack of control by stewards and police.

After winning the LDV Vans Trophy in 2006, Trundle took to the pitch wearing a T-shirt depicting a Swansea fan urinating on a Cardiff City shirt.