Michael Gove has accused the EU of refusing to engage in negotiations on a new Brexit deal amid a deepening war of words between Westminster and Brussels.
Mr Gove, the Chancellor of the Duchy of Lancaster who is in charge of no-deal preparations, said he was "deeply saddened" by the European Union position, which was "not in Europe's interests".
In Brussels, the European Commission insisted it was open to talks but made clear Theresa May's Brexit agreement was "the best possible deal" Britain was going to get.
That position was underlined by Taoiseach Leo Varadkar, who insisted that the Withdrawal Agreement, including the backstop, could not be re-opened.
The latest exchanges followed reports from Brussels that EU officials had concluded that Boris Johnson's new government had no intention of negotiating and that its "central scenario" was a no-deal break on 31 October.
Following a meeting of the British government's Brexit "war cabinet", Mr Gove insisted the government was ready to engage in talks in a "spirit of friendliness".
However, he said the EU side had to accept a new approach was essential after Mrs May's agreement was rejected three times by the British parliament.
"We need a new approach and we stand ready to engage with the European Union, to negotiate in good faith to make sure that we can have friendly relationship in the future," he told reporters.
"We will put all our energy into making sure that we can secure that good deal but at the moment it is the EU that seems to be saying they are not interested.
"They are simply saying 'No, we don't want to talk'. I think that is wrong and sad. It is not in Europe's interests."
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Mr Johnson has said that while he wants to negotiate a new agreement, he is not prepared to open talks unless the EU side agrees to drop the backstop, which proved the key stumbling block to Mrs May's deal.
Speaking on a visit to Northern Ireland, Mr Varadkar re-iterated his invitation to Mr Johnson to go to Dublin for talks on the basis of "no pre-conditions".
At the same time, however, he said the Withdrawal Agreement could not be re-opened, although the EU could offer "clarifications", as well as possible changes to the Political Declaration on the future relationship between the UK and Brussels.
"Our position is that the Withdrawal Agreement including the backstop is closed. But there is always room for talks and negotiations," he said.
"We can certainly make changes to the Political Declaration and we have demonstrated before that it is possible to offer clarifications."
Mr Johnson's chief Brexit negotiator David Frost held talks in Brussels last week that a diplomat said led the EU to conclude there was currently no basis for "meaningful discussions".
"It is better to be prepared for 'no deal', because Boris Johnson is credible on this threat," a senior diplomat warned after being briefed on last week's talks.
"He will try to play on the fear of 'no deal' to try to divide Europeans. For the time being, the unity of the 27 is holding, but we will have to see," he said.
"The question is who's going to fold first, because Boris Johnson is following a political logic to keep power."
Annika Breidthardt, a spokeswoman for the European Commission, insisted that President Jean-Claude Juncker was "available if Boris Johnson wishes to discuss and clarify his position in person or by phone".
An EU source said Mr Frost had used last week's meeting to repeat their demand for the backstop to be thrown out.
Additional reporting AFP