LONDON (Reuters) – Britain’s Royal Bank of Scotland could have to shell out a further 900 million pounds to settle a final compensation bill for mis-selling payment protection insurance after a last-minute surge in claims from customers.

The state-backed bank said on Wednesday it had made an additional provision of 600-900 million pounds, on top of the 5.3 billion pounds ($6.51 billion) already set aside, as Britain’s costliest consumer banking scandal draws to a close.

British banks have so far paid out more than 36 billion pounds to consumers who were missold the loans insurance on a vast scale.

RBS said 4.9 billion pounds of its total provisions has already been utilised. The volume of claims received in August, in the run-up to the Aug 29 deadline, was significantly higher than expected.

The fresh provision will be reflected in the third quarter results, RBS said, adding that the processing of PPI claims were ongoing and the ultimate provision recognised could be above or below the 600-900 million pounds range, it added.

($1 = 0.8145 pounds)