UK Prime Minister Theresa May is preparing to make a major speech on Brexit amid accusations by the disgruntled outgoing top UK civil servant in Brussels that the government lacks an exit strategy.
Foreign Secretary Boris Johnson and Brexit Secretary David Davis are contributing to the content of the address, which is expected later in January.
Ms May will reportedly say Britain will pull out of the single market if the European Union fails to make concessions on freedom of movement, although sources insisted this was just speculation.
Ms May moved swiftly to draw a line under the row sparked by the surprise resignation of UK permanent representative Ivan Rogers by agreeing his replacement Tim Barrow within 36 hours of his notice to quit.
In a fiery resignation letter, Mr Rogers had hit out at the "ill-founded arguments and muddled thinking" of politicians and said civil servants still did not know the government's plans for Brexit.
A former Whitehall boss warned that the surprise resignation of Mr Rogers had exposed concerns about the government's state of readiness for withdrawal negotiations under Article 50, due to begin within less than three months.
Bob Kerslake said it "deprives the government of a very experienced and capable European expert at a critical moment".
But Mr Johnson said Mr Barrow was "just the man" to secure the best Brexit deal for the UK.