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A German industry boss has said it would be "very, very foolish" if the EU imposes trade barriers on the UK in the event it votes to leave the EU.

Markus Kerber, the head of the influential BDI which represents German industry, said his organisation would make the case against such measures.

He said any introduction of tariffs would be "regression to times we thought we'd left behind in the 1970s".

The UK's referendum on whether to leave the EU will be held on Thursday.

"Imposing trade barriers, imposing protectionist measures between our two countries - or between the two political centres, the European Union on the one hand and the UK on the other - would be a very, very foolish thing in the 21st Century," Mr Kerber told the BBC's World Service.

"The BDI would urge politicians on both sides to come up with a trade regime that enables us to uphold and maintain the levels of trade we have, although it will become more difficult."

Mr Kerber added that any introduction of tariffs would lead to job losses in Germany and the UK.

He said a vote to leave the EU would lead to a "serious disruption" to the German-UK economic relationship, describing it "as if a relative had left the family".

The German government has taken a tougher line on a future trade arrangement, should the UK vote to leave. Germany's finance minister Wolfgang Schaeuble has said a leave vote would mean Britain leaving the European single market - "out is out".

Leave campaigners say the UK does not need to be part of the single market.

Should the UK request a trade deal, a senior MP in Angela Merkel's Christian Democratic Union, Juergen Hardt, says the EU would not be able to negotiate a trade pact with the UK quickly.

"I'm sure we'll find ways again to link Britain to Europe, but it will be tougher for Britain," he said.

He said the EU was busy trying to do a deal with the US. On a UK deal - should one be requested - he said "there will be negotiations but (it is) not a priority".

Germany - an architect of the European Union - is gripped by the possibility of a British exit from the EU, with wall-to-wall TV coverage of the referendum campaign.