IT “remains to be seen” whether Theresa May’s stance on Brexit will prove acceptable to EU negotiators, the boss of Dorset Chamber of Commerce and Industry (DCCI) has said.

Theresa May set out more details of her vision for a future economic relationship with the European Union.

She said her plan could deliver an “optimistic and confident future” that would make Britain “a stronger and more cohesive nation”.

DCCI chief executive Ian Girling said: “It still remains to be seen how acceptable her position is by negotiators in Brussels and how much movement there will be in the final agreements.

“The outcome of negotiations over such issues as any customs arrangement will have a material effect on business in Dorset, especially those involved in international trade.

“We would strongly urge Mrs May and negotiators to take the momentum generated by this speech into the next round of discussions. The more certainty business has at the earliest opportunity the better as it will mean they will have more time and greater confidence to plan and invest in the future.”

In a speech at London's Mansion House, the prime minister set out five "foundations" to underpin the new relationship – including binding commitments to fair competition and a new arbitration mechanism to resolve disputes.

She repeated her "red lines" that the UK will leave the single market and customs union and the jurisdiction of the European Court of Justice, but she also spelt out greater details on the customs arrangements where Britain wants to avoid a hard border on the island of Ireland.

Poole MP Sir Robert Syms, who campaigned for the Leave side in the 2016 EU referendum, said: "I think the prime minister set out a sensible pragmatic approach which I fully support."

Bournemouth West MP Conor Burns, another Leave supporter, said the prime minister had set out a Brexit based on an “ambitious free trade agreement”.

“We are their largest market, they’re our largest market. She’s made it clear it’s not a surprise that, given we start with the same regulations, there will be areas where it’s best to carry on in ‘regulatory alignment’, but there are other areas where we will want to do things differently," he said.

“It outlines a form of Brexit that will be a special partnership with the EU but delivers on the referendum result and the promise made to control our laws, control our borders and stop large payments from Britain to the EU.”

Mrs May declared she was "confident" that a deal was "achievable" and said her message to Brussels was: "We know what we want. We understand your principles. We have a shared interest in getting this right. Let's get on with it."