Business leaders raised concerns about a lack of clarity from the Government over plans for Brexit as Chancellor Philip Hammond said it would be "madness" not to seek to retain the closest possible links with the European Union.
Senior industry figures were invited to a meeting with Brexit Secretary David Davis amid concerns the views of businesses were not being listened to as the country negotiates its withdrawal from the EU.
Business leaders said they were pleased ministers were listening but a source said there was still uncertainty about the Government's vision for Brexit.
In a sign of their concerns, CBI director general Carolyn Fairbairn has called for Britain to remain a member of the single market and the customs union until a free trade deal with the remaining 27 member states is finalised.
But Mr Hammond, speaking at the G20 summit in Hamburg, said he wanted to "negotiate a transitional structure which takes us outside of those memberships" but "replicates as much as possible" those arrangements until a new free trade deal with the EU is in place.
He said the new deal should mean the UK retains close ties to the EU countries: "It would be madness not to seek to have the closest possible arrangement with them going forward."
Ms Fairbairn's concerns were raised in the meeting with Mr Davis at Chevening House in Kent, the grace-and-favour country residence he shares with Foreign Secretary Boris Johnson and International Trade Secretary Liam Fox.
One source at the meeting said they were "not sure we got any clear answers" about the plans for transitional arrangements and added: "I think what business really wants is clarity on what we are trying to achieve and then make it as smooth as possible how we get there".
"What we would like is to get some more clarity and certainty over what the vision is," the source said.
But business leaders welcomed the fact the meeting had taken place, hoping it marked a change of tone from the Government.
Terry Scuoler, chief executive of manufacturers' organisation EEF, said: "This meeting has been a good first step and it's clear ministers are listening to business concerns, which we welcome.
"We had an open and frank discussion and we've started a process where we will work together to obtain as much clarity and certainty as possible for industry as we prepare to leave the EU."
Federation of Small Businesses policy director Martin McTague said: "I was very encouraged that government ministers seemed in listening mode and committed to achieving a pro-business Brexit.
"They made clear at the meeting, which included a number of big business leaders, that the needs of SMEs would be top of the priority list when looking at our future outside of the EU.
"There was strong recognition from ministers that small businesses would be the least able to cope with trade barriers, both in terms of tariffs and bureaucracy. And I was heartened by the recognition of the benefits of free trade, and a clear moral drive that our future success will rest upon it."
Speaking at the G20 summit, Theresa May said she wanted to ensure the UK continued to enjoy a good trading relationship with the EU.
However, she said the country could not be a member of "every part of the customs union" and make its own trade arrangements with other countries outside the EU.
"What we will be discussing as part of our negotiations for the future arrangements is we do want to ensure that we can trade around the rest of the world," she told Sky News.
"That means we can't be members of every part of the customs union.
"But we want to continue to have tariff-free and as frictionless trade across borders as possible because we want to ensure that we have that good trading relationship with the EU."
Tory Suella Fernandes, a ministerial aide who chairs the influential European Research Group, insisted that Brexit would be "meaningless" unless the UK was out of the single market and customs union.
But she insisted that "frictionless" trade was possible and dismissed warnings by Brussels' chief negotiator Michel Barnier as "hype" at the start of the negotiations.
Mr Barnier said on Thursday it was "not possible" to have all the benefits of the single market without being a member, or enjoy frictionless trade without being in the customs union.
But Ms Fernandes told BBC Radio 4's Any Questions: "We are right at the beginning of these negotiations and it's natural for both parties to hype up their positions. The Lions are playing rugby this weekend and both teams are going to hype themselves up for the match - it's the same with the negotiations, both teams will emphasise what they want in an ideal situation.
"The whole point of a negotiation is that you reach a middle point."
She said for the referendum result to mean "anything at all", the UK must "regain control over our trade policy, we need to get out of the single market and the customs union".
"If we don't do either of those things, Brexit is meaningless so to honour that decision last year we have to leave the customs union and we have to get a free-trade agreement with the EU."