UPDATE 1-BoE sticks with anti "window dressing" rule for bank leverage ratio

* BoE dismisses concerns over dual ratio reporting

* Banks says two systems will be costly, potentiallyconfusing

* BoE says up to banks to explain differences in figures (Adds more detail from BoE statement)

By Huw Jones

LONDON, Dec 7 (Reuters) - Britain's banks will get an extrayear to December 2017 to prepare for publishing more detailedinformation on their leverage ratios or the broad measure ofcapital to non risk-weighted assets, the Bank of England said onMonday.

The BoE's supervisory arm, the Prudential RegulationAuthority (PRA), said it would go ahead with imposing a strictermethod on UK lenders for calculating leverage ratios thanrequired under global rules.

In July it proposed that banks also use the daily average ofthe ratio for calculating the end of quarter figure forpublication to avoid "window dressing", or attempts to flatterthe figure around the reporting date.

This would be in addition to the "point in time" end ofquarter figure.

Some banks said this would be burdensome, but the BoE saidit would go ahead with daily averaging, though it has agreed todelay the start date for publication - but not privatelyreporting to regulators - to give lenders more time to get thesystem's accuracy right.

"Based on the above, the PRA considers it appropriate toextend the transitional period for daily averaged disclosuresfrom 12 months, that is ending on 31 December 2016, to 24months, that is ending on 31 December 2017," the PRA said in astatement.

"This would mean that there is a period where the dailyaveraged number is being reported to the PRA but not publiclydisclosed, which would allow firms additional time to improvethe accuracy and comparability of the averaged numbers withoutcompromising the effective monitoring of the UK leverage ratioframework," it said.

The leverage ratio is a separate "backstop" to a bank's coreratio, which measures capital to risk-weighted assets.

The more stringent approach of using "daily averaging" willmove Britain in line with the United States and is the latestattempt by regulators to stop banks "gaming" the capitaladequacy system.

Policymakers have said that such steps are needed to restoreinvestor trust in a sector tarnished by the 2007-09 financialcrisis that found lenders were under capitalised.

Some banks told the PRA's consultation that disclosing adaily-averaged leverage ratio in addition to the "point in time"figure" may lead to investors "misinterpreting" the data.

But PRA said on Monday it was essential to have a credibledisclosure regime and that it would be up to banks to explainthe market differences between the two figures.

(Reporting by Huw Jones, editing by Louise Heavens and SusanThomas)