It is one of the most enduring truths in Premiership football and a crumb of comfort for the bitter Manchester City fan. But the cliche of the Manchester United faithful making the trip to Old Trafford from Bournemouth each fortnight may have to be relegated to the realm of myths.
Analysis of both clubs' season ticket-holders has revealed that hard-core reds are just as likely to be locals as their blue counterparts.
Adam Brown, a senior research fellow at the Manchester Institute for Popular Culture at Manchester Metropolitan University, has probed the relationship between the two clubs and their supporters in a project funded by the Economic and Social Research Council.
His findings contradict the popular belief that City supporters are loyal locals and United supporters "glory hunters" from the south of England.
In fact, 40 per cent of City's season ticket-holders and 30 per cent of United's come from within the Manchester postcode area, while about three-quarters of both groups are based in the Northwest.
Although Dr Brown conceded that United shirts were still more likely to be seen than City shirts in places such as Torquay, he said the analysis demonstrated how the global branding of United has not altered the core of the underlying fan base.
"To have such similar patterns of support suggests that things haven't 2changed as drastically as some people portray," he said.
Dr Brown said neither club had significant numbers of season-ticket holders living near its ground. But this was due partly to depopulation of the city centre in a flight to the suburbs.
Andy Walsh, a committee member of the Independent Manchester United Supporters Association, which campaigned against BSkyB taking over United, said the jibe of "southern glory hunters" was a lazy one spawned by the wide support for the club across the UK and abroad.
"While the business managers of football clubs chase a wider market, those who pay to watch the team are very much part of the city in which the club resides," he insisted.
But Phil Gatenby, secretary of Manchester City's independent Centenary Supporters Association, said he was certain that a high proportion of Old Trafford's gate was still likely to have travelled from Norway and Malta to watch the match.