FRANKFURT (Reuters) - German engineering group Siemens (>> Siemens AG) said it was committed for the long term to Britain, which will begin the formal process of leaving the European Union on Wednesday.

The trains-to-turbines group employs more than 15,000 people in Britain, has played an important role in London's Thameslink and Crossrail rail projects and is investing 160 million pounds in a wind turbine-blade factory in Hull.

"While the exact terms of the UK's exit from the European Union are unclear, we are committed to London in the long-term," Siemens' UK Chief Executive Juergen Maier said in a statement.

Deutsche Bank (>> Deutsche Bank AG) also gave a vote of confidence in Britain's capital by choosing a new office for its London headquarters last week.

Google , Facebook (>> Facebook Inc), Apple (>> Apple Inc.), Snap (>> Snap Inc) and Amazon have also announced investments in London, although entrepreneurs have warned that the city risks its status as a start-up destination if the government does not clarify how it plans to keep the best talent.

Siemens did not detail its UK investment plans on Monday.

(Reporting by Georgina Prodhan, editing by Louise Heavens)