BARCLAYS has put aside £500 million to settle so-called forex - foreign exchange - rigging allegations as it finalises talks with global regulators investigating the scandal.

The bank, which is reportedly one of six in discussions to reach a settlement before the end of the year, gave the first indication of how much it was likely to cost as it published third quarter results yesterday.

Barclays announced the latest provision as it published results showing a four per cent rise in pre-tax profits to £1.22 billion for the third quarter.

It said a £500m provision had been recognised "relating to ongoing investigations into foreign exchange with certain regulatory authorities".

Finance director Tushar Morzaria said the sum was "our best estimate based on the dialogue that we are having with certain regulatory agencies". But he would not be drawn on whether the provision was likely to be enough to draw a line under the bank's involvement in the affair or whether more money might be needed.

Barclays also announced that it was setting aside an additional £170m for redress in the mis-selling of payment protection insurance (PPI), taking the pot it has set aside to more than £5bn. However, it has pared down its total provision for a separate scandal, over complex financial products known as ­interest rate swaps, after a review of the episode neared completion. The sum set aside has come down from £1.5bn to £1.34bn

Barclays' wider financial results were better than some analysts expected with adjusted pre-tax profits excluding the costs of its Transform restructuring programme up 29 per cent to £1.92bn.

Investec's Ian Gordon said: "Barclays continues to confound its sceptics."