UPDATE 1-UK's biggest banks face further $29 bln misconduct bill - S&P

* 'Big 4' already incurred 42 billion pound misconduct bill

* S&P sees further PPI charges of over 5 billion pounds (Adds details)

LONDON, April 27 (Reuters) - Britain's biggest banks faceanother 19 billion pounds ($29 billion) of charges relating topast misconduct over the next two years, ratings agency Standard& Poor's (S&P) said in a report on Monday.

S&P said Britain's banks and customer-owned lenders hadincurred 48 billion pounds in misconduct and litigation chargesover the past five years.

Britain's four biggest banks -- Barclays, HSBC, Lloyds Banking Group and Royal Bank ofScotland -- accounted for 42 billion of that total,equivalent to about 7.5 percent of their revenues, S&P said.

S&P said the mis-selling of payment protection insurance(PPI) on loans and mortgages had so far cost the banks more than26 billion pounds. It expects banks to face over 5 billionpounds of further PPI charges in the next two years.

Banks also face litigation charges arising frominvestigations into the alleged rigging of foreign exchangemarkets and benchmark interest rates and probes into breaches ofanti-money laundering controls.

S&P said it believed the affected banks had sufficientcapital buffers to cope with the charges.

The charges came on top of almost 16 billion pounds spent bythe banks restructuring their business models following the2007-9 financial crisis and 5 billion pounds of expensesrelating to the government's bank levy, S&P said.

($1 = 0.6605 pounds) (Reporting by Matt Scuffham; Editing by Sinead Cruise and MarkPotter)