May tries aims to soothe fears of business leaders at key speech in London, saying doors will open to “old allies”.

British Prime Minister Theresa May has told business leaders in the UK that while leaving the European Union creates uncertainty in the market, there will also be opportunities for “dynamic trading agreements”.

Speaking on Monday at the annual Confederation of British Industry conference in London, May said that the doors would be open to doing business with “old allies” in other parts of the world.

She also said that her government would invest an extra $2.5bn in science research and development by 2020, and committed to plans of the previous government to introduce a 17 percent rate for corporate tax – the lowest in the G20.

“Today, Britain has firms and researchers leading in some of the most exciting fields of human discovery,” she said.

“We need to back them and turn research strengths into commercial success.”

Al Jazeera’s Laurence Lee, reporting from London, said that businesses are worried about the instability caused by the lack of knowledge as to what a “Brexit” – or Britain’s departure from the EU – will actually look like.

“Theresa May and the government can’t and won’t tell [the business leaders] because that will give away their negotiating position to the European Union,” Lee said.

After having narrowly voted in favour of leaving the EU, the UK will have to negotiate the terms of its exit with the union’s other member states.

Business leaders voiced concerns to the prime minister on Monday about the impact of Britain’s departure from the EU, and the uncertainty surrounding the country’s future trading terms with member states.

“Businesses are inevitably considering the cliff-edge scenario — a sudden and overnight transformation in trading conditions,” said Paul Drechsler, CBI president.

“If this happens, firms could find themselves stranded in a regulatory no man’s land.”

Others echoed the business chief’s concerns.

“I’m not too optimistic about Brexit,” a representative from German engineering firm Bosch told AFP news agency, speaking on condition of anonymity. “I don’t see things moving in the right direction”.

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May also told businesses “how to behave”, according to Lee.

“She went on to give businesses a bit of a lecture.”

“She basically said [Brexit is] a bit of a wake-up call because the working people in the country don’t like to see the businesses get very rich while they’re getting poorer. She said [public] trust in business was at 35 percent, that businesses had to embrace reform,” our correspondent said.

May also said that the government intended on being more interventionist with regards to corporate governance, such as enforcing harsher tax laws.

“She said that businesses needed to give back to communities that served them,” Lee reported.

“Clearly, that’s a completely different set of priorities from the businesses which want to get back into the EU to avoid tariffs – she says she is working for the working poor in the country.”