Brentford fans have been stung by fraudulent payments being taken from their bank accounts after booking play-off final tickets online.

The Bees used third-party ticketing agency Ticketzone to handle the bulk of sales for the League One play- showdown with Yeovil Town at Wembley.

But many supporters have been shocked to find that after registering their bank details with Ticketzone further unauthorised transactions have been made.

Brentford fan Tim Ward, 46, said he received a call from Natwest’s fraud team yesterday alerting him that several transactions on his card had been declined.

He said: “I was told that on Tuesday a payment of £3,500 to Barclaycard had been declined as well as £900 tried to be taken to Nationwide the next day.

“It all happened quite suddenly – I half noticed something about a ticket scam on a Brentford internet forum but when I got the call from Natwest I wondered if that was a scam itself.

“A number of smaller transactions did go through, including a £1 payment to Vodafone and others to O2.”

Supporters have been taking to forums and Twitter to complain of fraudulent activity on their cards, ranging from 65p to more than £20,000.

The illegal activity came to light when Bradford City fans, using Ticketzone to handle sales for their League Two play-off final, alerted their Brentford counterparts online.

Brentford’s chief executive confirmed the club would investigate the matter and discuss it with Ticketzone.

A Ticketzone spokesman said: “This is something we are investigating at the moment. I can't comment any further at this stage.”

On Bradford’s website, Ticketzone wrote: “A very small number of queries have been reported to Ticket Zone and these are under further investigation.

“All these occurrences have been forwarded to their card retail banking providers, who are investigating the matter further.

“No evidence has been found, at this time, of any anomalies or security issues with Ticketzone’s web sales structure.”

Ticketzone has handled more than 35,000 tickets transactions for Brentford and Bradford City supporters in the past two weeks.

It also handled Brentford ticket sales for the 2011 Johnstone’s Paint Trophy Final, also at Wembley, when few customer service issues were reported.

However, Swindon Town fans complained of similar fraudulent activity after booking tickets through Ticketzone for their play-off final in 2010.

As of 9pm on Wednesday, Ticketzone informed Brentford it had received only two complaints about the issue – despite more fans alleging on internet forums to have registered their complaints with the Devon-based company.

Brentford fans who have booked through the Ticketzone should contact their banks as well as Ticketzone directly.