UPDATE 2-'Hard Brexit' could cost British finance firms 38 bln pounds

* 75,000 jobs could be at risk if 'hard Brexit' study says

* Speculation finance sector could lose access to singlemarket

* Treasury says working to keep firms' access

* Some see opportunity for the City in Brexit (Adds Treasury comment)

By Andrew MacAskill

LONDON, Oct 5 (Reuters) - Britain's financial industry couldlose up to 38 billion pounds ($48.34 billion) in revenue in aso-called 'hard Brexit' that would leave it with restrictedaccess to the European Union's single market, according to areport commissioned by an industry group.

If finance firms lose the right to freely sell theirservices across Europe, 75,000 jobs may disappear and thegovernment may lose up to 10 billion pounds in tax revenue, thereport by consultancy firm Oliver Wyman said.

The study is one of the first to outline the impact onfinancial services of Britain's vote in June to leave the EU.

The findings have been presented to the UK Treasury andother government departments, according to people with knowledgeof the talks.

There is growing speculation that the finance sector, whichincludes retail banks, asset managers, insurers and investmentbanks, will lose access to the single market when the Britishgovernment negotiates its EU exit.

"It is in everyone's best interests for there to be apositive outcome to the negotiations that is mutually beneficialto the UK and the EU, causes minimum disruption to the industryand benefits customers," Hector Sants, vice-chairman of OliverWyman, and Britain's former top financial regulator, said.

The report was commissioned by the main industry lobby groupTheCityUK.

Banks based in Britain are pushing for the government tosecure a transitional period for their industry in case itproves difficult to negotiate a favourable deal for theindustry.

The Treasury said in a statement it is working to ensurecompanies continue to have access to the single market.

"The government has been speaking to the financial servicesindustry to make sure that we understand fully the issues thatmatter to it as we prepare for negotiations to leave the EU,"the Treasury said.

The future of London as Europe's financial centre will be amajor negotiating point in Brexit talks with the EU because itis Britain's largest export sector and biggest source of taxrevenue.

Britain's financial services sector generates between 190 to205 billion pounds of revenue each year and employs about 1.1million people, the report said. The industry pays about 60 to67 billion pounds in taxes.

The report outlines the impact of two different Brexitscenarios.

In the worst-case scenario, international banks would loseall access to the single market, known as a 'hard Brexit', whichwould lead to a fall in revenue of between 32 to 38 billionpounds and put 65,000 to 75,000 jobs at risk, the report said.

If Britain keeps its access to the European Economic Area onsimilar terms to now then only 4,000 jobs might disappear and itwould lose about 2 billion pounds in revenue.

Property investor Richard Tice, chairman of a new lobbygroup pushing the government for a clean break with the EU, saidthe report was exaggerated and other European capitals lackedthe infrastructure or skills to take financial services businessfrom Britain.

The report is "designed to scare people with specialpleading. However, it lacks credibility," he said. "Brexit is ahuge opportunity for the City."

Pro-Brexit supporters say the City could benefit from lowerregulation and by refocusing on faster-growing economies inAsia. ($1 = 0.7862 pounds) (Reporting by Andrew MacAskill in London; Editing by AlistairBell and Jane Merriman)