Theresa May failed to quell business uncertainty over Brexit as she delivered a warning to her European counterparts that she would be willing to walk away with no Brexit deal.

In her much-anticipated Brexit blueprint speech the prime minister confirmed the UK would leave the single market – but said she would seek a new free trade deal, insisting a good deal for the UK would also be good for Europe.

On the continent, reaction to her speech was mixed. While European Council president Donald Tusk said it gave the EU a 'more realistic' view and remaining states were 'united and ready to negotiate', others reacted angrily.

Jan Philipp Albrecht, a Green Party MEP for northern Germany, launched a four-letter tirade against the Prime Minister, claiming leave voters had expected the UK to stay in the common European market.

Mrs May indicated that leaving the European Union, and the current customs union rules, would allow Britain to do deals with countries in other parts of the world.

It comes after US president-elect Donald Trump, who will be inaugurated on Friday, said Britain was not 'at the back of the queue', but at the front of the line for a deal.

Paul Reeve, managing director of Cromer-based Structure-flex Ltd said exports were crucial to the success of his business. Last year they represented about 50pc of the firm's £7m turnover, with both the USA and EU countries among global customers, and leaving the single market would definitely affect business.

Structure-flex, which employs 70 to 80 people, makes a range of heavy-duty coated textile products including lorry curtain sides and building wraps, won a Queen's Award for International Trade in 2013.

'In Europe we have become more competitive with the demise of sterling over the past two months, but when we leave it will depend on the stance each member of the EU takes on our products being imported into their countries,' said Mr Reeve.

'If there are already businesses making comparable products within the EU, we may find we are treated more harshly in terms of tariffs and import rates.' In turn, many of Structure-flex's suppliers were in Europe and could find in future that their products were subject to import taxes imposed by the British government, adding to the costs.

'It's difficult to know if it's going to be good or bad until we see what tariffs are applied to our specific products,' he added.

Mr Reeve believed the UK could probably strike a good deal with the USA, which seemed keen to act quickly. He suspected that Mr Trump hoped to use an attractive trade deal to 'entice' other EU member countries to follow the UK's Brexit example. Mr Reeve hoped it would include lower import taxes.

Jacyn Heavens, the founder and chief executive of Epos Now, who was in New York yesterday, said he thought the UK was in a good place because of its strong ties to America, and because it had moved quickly to capitalise on Mr Trump's pro-Brexit stance.

The boss at the Norwich-based company which supplies till equipment and cloud-based software, said leaving the single market would be difficult for the business, but it would also affect customers who might put European expansion plans on hold.

He said they would have to 'wait and see what Europe comes back with' after Mrs May's speech, and they had decided to focus their efforts in the US and the UK and look at Europe again 'later down the line'.

Graham Hacon, chief executive of Great Yarmouth-based offshore services firm 3sun Group, said the company had seen a boost since sterling's devaluation, and around 50pc of the company's expected £26m turnover this year would be generated from work on the continent.

But he said: 'If you look at the emerging markets for offshore wind, the big global powerhouses are the US and China, and we have had active trade missions to those countries.

'But the bulk of offshore wind activity for the next two to three years is forecast to be in UK waters, which may lead us to take a more UK-centric view.'

With multi-billion pound wind farms being built off East Anglia for the next decade, Mr Hacon said potential tariffs or barriers to continental firms could boost businesses in the UK.

Andrew Dewing, chief executive of Aylsham-based grain merchant Dewing Grain, said he thought it looked like they were going to have to start paying a tariff to get their products into Europe, which would mean products would cost more.

'We export about 10pc of our wheat and barley to Europe, mainly to Ireland and Holland, and it is going to be less competitive,' he said, adding: 'The effect is probably going to be that there is a drop in prices for farmers.'

NFU East Anglia regional director Robert Sheasby welcomed Mrs May's acknowledgement in her speech that Britain needed a reliable workforce from overseas but warned the Britain's ability to trade with Europe was going to be incredibly important with 78pc of its wheat and barley exports, and a significant percentage of its bean and pea exports, going to Europe.

'Access to that market is going to be important and we are going to need some early indications of what that might look like.

'Negotiating a free trade agreement can take years to secure and we want some certainty there will be a strong transitional process, we don't want to fall off a cliff edge.

'The risk is that if we can't secure a sensible transitional agreement some of our members businesses will find it hard to trade.'

Liberal Democrat leader Tim Farron said Mrs May was putting thousands of local jobs at risk by waving the flag on the UK's membership of the Single Market before the negotiations had even begun.

'East Anglia is Britain's gateway for trade with Europe, meaning the economy here thrives from being able to export freely with single market,' he said.'

Should we be leaving the single market? Email edpletters@archant.co.uk

Will the EU call her bluff? Annabelle's column on page 27