In the past, rivalry between the two clubs has gone beyond the action on the field at Old Trafford and Elland Road. Hostility became more intense over the years and during the 1970s, when British football hooliganism was at its height, fights between the Leeds United Service Crew and Manchester United's Red Army, two of the most notorious hooligan firms in Britain, were commonplace and became known as some of the most violent clashes in British football. Many people were injured in these encounters but violence between fans of the clubs has declined sharply since the 1970s for a number of reasons, mainly due to the general reduction in hooliganism. As recent as January 2010, prior to the two clubs meeting in the FA Cup 3rd round, Manchester United manager Sir Alex Ferguson described the matches as "fantastic, feisty occasions" with an "electric" atmosphere. The rivalry has also been labelled by The Daily Telegraph as "English football’s most intense – and inexplicable – rivalry".
These encounters have been particularly scarce since 1982, the year that Leeds were relegated to the Second Division. Hooliganism was still rife among fans of English league clubs at this stage, and by the time Leeds returned to the top flight in 1990 the problem was less severe and has remained a lesser problem since. The rivalry and the hooliganism have been effectively curtailed since 2004, when Leeds were relegated from the Premier League. The teams have met only twice since then, and while polling shows Leeds fans still consider Manchester United to be their main rivals, Manchester United fans consider Liverpool to be their main rivals, followed by Manchester City, Chelsea and Arsenal.
The rivalry is considered to be a sporting manifestation of the established rivalry between the counties of Yorkshire and Lancashire, which can loosely be traced back to the Wars of the Roses, a series of civil wars fought between the rival Plantagenet royal houses of York and Lancaster for the throne of England during the 15th century. The battles contested during the wars were particularly bloody, especially the Battle of Towton, which took place just 15 miles (24 km) away from Leeds and is described as "England's bloodiest ever battle".
The colours of each football team's home shirts fittingly correspond to the respective rose representing their historic county – Leeds with a white kit, resembling the Yorkshire rose and Manchester United with a red shirt, like the Lancashire rose. However, Manchester United's colours have not always been red and Leeds only adopted their white kit in the 1960s, inspired by Real Madrid. There is a similar rivalry in the sport of cricket, in which matches are contested on a county basis. In this case, the Roses Match is the name given to games played between Yorkshire County Cricket Club and Lancashire County Cricket Club. Although the clubs cover the larger county region, Yorkshire are based in Leeds and play at the Headingley Stadium, while Lancashire play at the Old Trafford Cricket Ground in Manchester, close to the football stadium of the same name. Manchester is now in the metropolitan county of Greater Manchester, while Leeds is now in the metropolitan county of West Yorkshire.
A direct rivalry between the cities of Leeds and Manchester sprang up during the Industrial Revolution in Britain during the 18th and 19th centuries. The entire country was going through an unprecedented phase of economic growth and Leeds' economy had grown rapidly thanks to the woollen industry. Meanwhile, to the west in Manchester, the cotton industry began to flourish, with factories fuelled by the transportation of cheap coal down the Bridgewater Canal.