BT and One2One have lost their latest legal bid to prove that they were treated "unfairly and irrationally" over the payment of third generation mobile phone licence fees last year.

The court of appeal today rejected their claim that the government was wrong to give rivals Vodafone and Orange extra time to settle their multibillion pound bills.

The timetable was extended for Vodafone and Orange because, under auction rules, they were required to break the relationship formed by Vodafone's takeover of German rival Mannesmann - the then owner of Orange.

However, BT and One2One argued that the 16-week payment extension saved their rivals £170m in interest payments and constituted unlawful state aid.

BT and One2One each paid £4bn for their licences but had to pay in May last year, while their competitors were given until September.

Their lawyers argued that the Department of Trade and Industry, which oversaw the auction, should have either granted Vodafone and Orange licences immediately, kept them out of the auction altogether or delayed the payment schedule for all participants.

They claimed that the interest payments saved by their rivals broke EU fair competition laws.

But court of appeal judges today upheld a high court judge's earlier rejection of the claim.

A BT spokesperson said the group was "disappointed" with the decision, but said it intended to petition the law lords for leave to appeal.

He added that BT and One2One intended to claim compensation from the government if their complaints were upheld.