In the end it took three days, and struggled to get away from the issues at the heart of the controversy surrounding charges that many borrowers are calling unfair and illegal.

Rather than a dry legal hearing, it became a dress rehearsal for a trial - as both sides argued over whether it was fair that banks charged customers for running up unauthorised overdrafts.

"We effectively had a mini-trial," Mr Brennan said after the hearing.

"You are not supposed to have a mini-trial, but that is exactly what we did. At least it shows there are arguable issues."

The key issue is that a full trial would force the bank to justify why it charges quite so much when people go overdrawn without permission - something the bank has refused to do so far.

At the heart of the argument were charges of £28 per month for being in the red without permission, and a further charge of £38 that the bank imposed for every bounced cheque or standing order.

"The charges are unfair because they do not reflect the actual loss to the defendant," said Mr Brennan.

He added that the trial should go to court because it "would have significant impact beyond the claimant and the defendant".