As the government prepares to spell out its demands this week, the Confederation of British Industry (CBI) appealed to the government to limit bureaucracy for firms that are already fearful of a no-deal exit at the end of the year.
Senior ministers are expected to sign off on the UK's negotiating blueprint on Tuesday, which will underline the prime minister's desire for a Canada-style trade deal with limited tariffs on goods.
But Downing Street's hardline stance has already set the UK on a collision course with Brussels, with EU chief negotiator Michel Barnier explicitly ruling out a deal similar to the agreement the bloc has with Canada.
It comes after French president Emmanuel Macron cast doubt on whether a deal could be reached before the end of the Brexit transition period in December, setting up for a new cliff edge at the end of the year.
Dame Carolyn Fairbairn, CBI director general, unveiled a string of demands for British officials going into the talks, including trusted trader schemes, simplified paperwork for customs checks and reciprocal mobility agreements for business trips to European countries.
She said: “The message is clear: keep trade easy and minimise red tape. For this reason, British firms back many of the government’s objectives set out in the negotiating mandate, such as on zero tariffs and data.
“In other areas, how the government strikes the balance between access and control is less clear. All efforts must be made in these talks to save exporters time and money, avoiding new paperwork, costs and delays.
"This will protect the UK’s global competitiveness, jobs and growth. The unique challenges facing Northern Ireland businesses should also be front of mind for negotiators."
The UK's negotiating mandate will be published on Thursday – ahead of the start of formal talks next week, led by the prime minister's chief negotiator David Frost.
The blueprint for US trade talks is also expected in early March, which No 10 hopes will ramp up the pressure on Brussels by allowing the UK to negotiate both deals at the same time.
Government insiders said there was complete unity on the UK side while accusing the EU on being delayed by indecision and competing interests of different member states.
A Downing Street source said: “We left the EU on 31 January in line with the referendum result.
"We regain full independence for the people of the UK at the end of this year: the negotiation is about defining the terms on which we do that.”
The row centres on whether the UK will sign up to "level playing field" rules on work and environemental standards, a key ask for Brussels which is seeking to ensure European businesses are not put at a competitive disadvantage.
But Mr Johnson and Mr Frost have both said publicly that they have no intention of sticking to EU rules now that the UK has left the bloc.
In a sign of the trouble ahead, Mr Macron told fishermen at a meeting in Paris: "I am not sure that an agreement will be reached between now and the end of the year.
"Anyway, it is going to become more tense because [the British] are very hard."
Elsewhere, the government was warned against reneging on Brexit arrangements for Northern Ireland designed to prevent a hard border on the island of Ireland.
Concern has been expressed over reports that Mr Johnson has ordered his Brexit team to find ways to "get around" the Northern Ireland protocol to evade Irish Sea checks on goods passing from Great Britain to Northern Ireland.
Former Irish ambassador to the EU, Bobby McDonagh, said: "If UK government were to renege on its legal obligations under the Brexit withdrawal agreement to protect the Good Friday Agreement it would have many consequences.
"One would the end of any prospect of a US-UK trade deal."
A government spokesman said: "The UK signed the withdrawal agreement, including the protocol, last month. The UK will comply with its obligations."
The EU's final negotiating mandate is also expected to be published in the coming days.