Which soccer team has the most loyal fans?

Arjun Kharpal, special to
Alex Livesey | Getty Images

Arsenal and Chelsea may be two of the biggest soccer clubs in the world, but their fans are the least dedicated among British clubs in the European Champions League, according to the latest research.

Scotland's Celtic fans are the most loyal, willing to travel far and wide to see their team play, according to flight comparison website Cheapflights. Meanwhile, Manchester United supporters are ahead of their rivals Manchester City when it comes to backing their club.

To judge the levels of fan loyalty, Cheapflights analysed flight search figures since August 29, when this year's draw for the Champions League soccer tournament was made. Celtic fans boosted demand for flights to Amsterdam, Barcelona and Milan – where their team will be playing away games -- by 1,604 percent at peak since the group fixtures were announced.

(Read more: Champions League success 'critical' for soccer teams' finance)

"Having previously received awards from FIFA and UEFA for having 'loyal and sporting behaviour' it is clear that Celtic fans are working hard to maintain their reputation," Ben Rosier, spokesperson told CNBC.

Manchester United's away leg draw at Real Sociedad's home ground in San Sebastian, Spain, drove a 539 percent week-on-week increase in searches for flights. The destination seeing the biggest peak in interest was Donetsk in Ukraine, where Shakhtar Donetsk plays, which saw a 1,940 percentage increase in flight searches from Manchester United fans.

Rival fans at Manchester City only drove a 236 percent increase in interest in flight destinations overall, compared to 254 percent for United.

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But Chelsea and Arsenal fans look least likely to follow their team into Europe with an average increase in traffic to Champions League destinations at 69 percent each.

Searches for flights to Basel where Chelsea play on November 26 were down 17 percent since the Champions League draw announcement, suggesting fans are planning to stay away from the game.

"Could it be that some of the club's super-rich fans are travelling by road or private helicopter from their Swiss tax havens and don't require cut-price options?," Rosier told CNBC.

The Champions League kicks off on Tuesday with teams such as Real Madrid and Bayern Munich in action.

—By CNBC's Arjun Kharpal: Follow him on Twitter @ArjunKharpal