The International Monetary Fund (IMF) has given a bleak assessment of the UK's prospects for leaving the European Union.

Presenting a report on the British economy to the UK Treasury on Monday, IMF managing-director Christine Lagarde said that "all Brexit outcomes" will entail costs for the UK economy.

"Any Brexit deal will not be as good as the current smooth process by which goods, people and services move now," Ms Lagarde said.

The IMF boss warned that a more disruptive Brexit would lead to a "significantly worse outcome", adding that the range of Brexit issues left to prepare for was "daunting".

Ms Lagarde said that the UK would need to negotiate 63 trade deals in the event of a "no-deal" departure from the European Union.

"That is a heck of a lot of work," she said.

"Critical" to reach a deal

Ms Lagarde said a no-deal Brexit would lead to a reduction in size of the UK economy, and that new post-Brexit trade deals were unlikely to offset the cost of leaving the EU.

This made it "critical" to reach a deal with the EU in order to avoid large costs to the UK economy, she added.

The IMF said it forecasts UK economic growth at 1.5% this year and next, "assuming the UK and EU reach a broad Brexit agreement".

Its projections are down from the 1.75% growth seen in the 2016/7 financial year, driven by "Brexit-related facts", it said.

Chancellor of the UK Exchequer, Philip Hammond, said the prospect of leaving the EU without a deal was "unlikely, but not impossible".

Mr Hammond warned that his country was at a "critical juncture", which should not be put at risk in the final stage of negotiations with the European Union.

Chequers plan

It comes as British Prime Minister Theresa May said her Brexit strategy was the only option in play that can avoid a hard border in Ireland – without ‘carving up the UK.’

The so-called Chequers plan, agreed by the British cabinet in July, has faced stiff opposition in both London and Brussels.

Some 80 Tory MPs have signalled that they would be willing to vote against the plan in the House of Commons – while chief EU negotiator Michel Barnier has warned that he is "strongly opposed" to key parts of it.

Speaking to BBC Panorama however, Mrs May said the plan is the only way to protect the union between Britain and the North while upholding the peace process in Ireland.