Siemens fears a vote to leave on 23 June would cast a shadow of risk over the prospects for the German group's £310m ($349m), 1,000-employee offshore wind hub in Hull, northeast England, which will from next year begin making blades and assembling turbines for use at the giant projects planned off the nation's coast.

The German industrial giant is worried about the potential impact of an EU exit on the prospects for the UK's domestic offshore wind plans, and the implications for possible future exports from a factory that is no longer inside the trading bloc.

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