Blackburn Rovers have expressed 'fury' at claims that fans are selling season tickets to Manchester United ahead of this weekend's Premier League match between the clubs.
United will win a record 19th English title if they avoid defeat at Blackburn's Ewood Park ground on Saturday, with Rovers looking for points in their quest to avoid relegation.
Now there are concerns that United supporters wanting to see their club break the current English record of 18 titles it shares with arch-rivals Liverpool will cause security problems if they are sat amongst Rovers supporters.
"Reports that some Blackburn Rovers supporters are 'selling' their season tickets to Manchester United fans ahead of Saturday's Barclays Premier League fixture at Ewood Park have brought a furious response from the club," said a statement on Rovers' website on Tuesday.
"Club officials - fully supported by Lancashire Police - warn that everything possible is being done to minimise the illegal practice and stress that any offenders will face strong and appropriate action."
"Rovers have information and intelligence of season ticket holders selling their tickets directly to United followers - there is even evidence of season tickets being advertised on the internet."
Blackburn managing director Tom Finn said: "This is a very disturbing situation, not to mention a criminal offence, and a situation we could well do without leading up to what is a massive fixture."
"We are currently monitoring things very closely and, where necessary, will cancel the season tickets, so denying entry to the stadium on the day."
"It also goes without saying that we need as many Rovers fans inside Ewood Park on Saturday as we can."
"Fervent home support has worked wonders for us in recent years and we need it again now."