Britain's trading ties with the EU's 500 million person single market will need to be redrawn in the wake of last week's referendum, leading to predictions from economists and rating agencies that growth will slow and foreign investment will fall.

Siemens has said its investment plans for a wind power factory in northern England were unchanged by the vote, but Maier said plans to export from that facility, and any future investments, would depend on the trade deal Britain negotiates with the EU.

"I think we're just going to have to accept that there is going to be uncertainty on this issue of trade tariffs," he told BBC Radio.

"Obviously the ideal model is one that offers us free trade, but I'm also totally realistic that, given the parameters the democratic vote has put us under - which is the free movement issue, I'm also clear that that is pretty unrealistic," he said.

Free movement of people is seen as a likely condition of any deal to grant Britain access to the EU's single market, but clashes with promises made by the 'Leave' campaign to introduce tighter controls on migration from the EU.

"My best hope is that relationships don't break down between our negotiators and the EU, that everybody stays positive about those and that ultimately we retain a close relationship," Maier said.

(Reporting by William James; Editing by Dominic Evans)