A growing row over Theresa May's apparent threat to pull security co-operation unless Brussels agrees a trade deal is a "misunderstanding", a Cabinet minister has insisted.
In her letter to European Council president Donald Tusk triggering Article 50, the Prime Minister warned that failure to reach a comprehensive settlement would lead to a weakening in collaboration in the fight against crime and terrorism.
Critics accused the Prime Minister of trying to make a trade-off between security and commerce.
Work and Pensions Secretary Damian Green said the two issues had been mentioned side by side because they were "all bound up in our membership of the European Union".
"It's not a threat, I think that's the misunderstanding," he told BBC Two's Newsnight. "It's absolutely not a threat."
Liberal Democrat leader Tim Farron said the letter was "utterly scandalous" and a "blatant threat", while Labour's Yvette Cooper, who chairs the Home Affairs Committee, said the PM should not be using security as a "bargaining chip" in the negotiations.
Foreign Secretary Boris Johnson, writing in the Daily Telegraph, said: "It is our clear desire and intention that we should continue to play a role as one of the indispensable guarantors of peace and stability in our continent.
"We want to continue to work with our counterparts on defence co-operation, intelligence sharing, counter-terrorism, foreign policy co-ordination - and much else besides - on an intergovernmental level.
"At the same time, the PM is right to spell out her vision of a Britain outside the single market - and outside the EU legal order - but able none the less to continue the trading relationship that is so important for businesses and consumers both sides of the Channel."
In a "historic moment from which there can be no turning back", Mrs May set the country on the path to life outside the European Union when she triggered Article 50 on Wednesday.
The Prime Minister immediately ran into resistance from German Chancellor Angela Merkel and the European Parliament over her goal of conducting negotiations on Britain's trade relations with Europe at the same time as talks on arrangements for Brexit.
Plans to repatriate more than 40 years of powers back to Westminster will begin immediately with the publication of the details of the Great Repeal Bill.
The white paper - Legislating for the United Kingdom's withdrawal from the European Union - will set out how the Government will deal with EU laws that cannot be easily converted.
Secondary legislation, known as statutory instruments, will be used to make technical changes with up to 1,000 pieces expected, nearly as many as MPs and peers usually deal with in an entire parliament.
Brexit Secretary David Davis said: "At the heart of the referendum decision was sovereignty. A strong, independent country needs control of its own laws. That process starts now.
"Converting EU law into UK law, and ending the supremacy of lawmakers in Brussels, is an important step in giving businesses, workers and consumers the certainty they need.
"And it will mean that as we seek a comprehensive new economic partnership with the EU, our allies will know that we start from a position where we have the same standards and rules."
In Mrs May's letter to Mr Tusk, she set out how it was "necessary to agree the terms of our future partnership alongside those of our withdrawal from the EU".
Mrs Merkel gave a frosty reception to the PM's plea, saying talks must first clarify how to unravel the commitments, rights and duties the UK has entered into over its 44-year membership.
"It is only if we have sorted that out that we can next - and I hope soon - talk about our future relationship," said the German leader.
Mrs May told the BBC's Andrew Neil she wants "everybody to know" what the withdrawal arrangements are and the terms of the future relationship by the end of March 2019, but there "may be a period of implementation" after the UK leaves the EU.
Asked if free movement would end within two years, Mrs May replied: "We want to have the agreements done in two years. There may then be a period when we are implementing those arrangements."
She added: "I did campaign for Remain and I did vote to Remain but I also said I didn't think the sky would fall in if we left the European Union and it hasn't."