Banking giant Barclays has set aside another £1.35 billion to cover payment protection insurance mis-selling, taking its total PPI bill to £4 billion.

The bank had already set aside £2.6 billion to cover redress to customers it had mis-sold the insurance to. (You don't need a claims handler to claim PPI back - see our guide on How To Reclaim PPI For Free).

Now that sum has increased to £3.95 billion, as Barclays said a drop-off in PPI claims per month had not been as quick as expected.

Last month, it was revealed that the total bill across the banking industry had broken the £10 billion barrier. (See our PPI mis-selling MSE News story).

It's not just PPI that was mis-sold by Barclays - the bank is also setting aside another £650 million to cover the mis-selling of complex interest rate swap products which were sold to small businesses, taking its total bill for this issue to £1.3 billion.

The mis-selling figures were released as Barclays revealed it was also taking action to shore up its finances. It's issuing new shares at a discounted price as part of a scheme to raise £12.8 billion pounds.

It follows demands from the City regulator, the Prudential Regulation Authority (PRA), that the bank should build up its cushion against future financial shocks.

The PRA, which is responsible for the regulation and supervision of banks, said it had "agreed and welcomed" the bank's plans to bolster its reserves.

Barclays chief executive Antony Jenkins says: "I am certain the decisive and prompt action we are taking will leave Barclays stronger."