The German economy will pay a “high price” if its leaders make life hard for the UK over Brexit, British pro-Leave campaigners are to warn.
John Longworth, co-chair of Leave means Leave, and ex-minister Owen Paterson will sound the warning at a major German business event on Saturday.
Britain will “walk away” if the deal is not right, Mr Longworth will say.
Theresa May has said it will be an act of “calamitous self-harm” for the EU to try and punish the UK for leaving.
The prime minister has said she wants the UK and the EU to be “good neighbours” in a constructive, new partnership after Brexit.
But she has warned that no deal will be better than a bad deal at the end of two years of negotiations – which are expected to start in April.
Mr Longworth, former British Chamber of Commerce director general, will echo these views at the Berlin event – attended by German ministers, business, academia and media.
“It is entirely sensible for businesses across the EU and Britain who wish to work and trade together to continue to do so and it would be helpful if the British and German governments, as well as key figures in the EU, work towards this goal,” he will say.
“If the German Chancellor and EU leaders continue down the road of negativity and threats when negotiating with Britain, German business and the German economy will pay a high price.”
‘Voice of business’
He will warn German businesses that the UK will revert back to World Trade Organisation rules “with ease” if it offers a bad deal.
He will suggest that the government could simply “compensate” business for any tariffs that are imposed on goods and services as a result.
“We want a system whereby free trade will continue, but in order for this to happen, you need to make representations to your government and the EU,” he will say.
“The voice of business must drown out that of the bitter politics of the EU project.”
Mr Paterson, a former environment secretary, will warn that “cack-handed” negotiations could have serious consequences for German exporters.
“Germany and the UK have a mutual, strategic and selfish interest in maintaining reciprocal free trade,” he will say.
“It is vital that businesses in key member states such as Germany are listened to carefully during the negotiations.”
Organised by Tönissteiner Kreis, a network supported by the main German industry federations, the gathering will explore the future of British-German relations after Brexit.
Foreign Secretary Boris Johnson has warned the rest of the EU against “punishment beatings” in the manner of a World War Two movie.
His comments were criticised by Labour and other opposition politicians.