German Chancellor Angela Merkel has told British Prime Minister Boris Johnson that his new Brexit plan is doomed to fail unless he budges on the Irish border issue. Meanwhile, the EU's Donald Tusk has accused the UK PM of playing a 'stupid' game.

Axar.az reports citing RFI that in a phone call on Tuesday, Merkel warned the British leader that a deal on Brexit was "overwhelmingly unlikely" unless he dropped his opposition to keeping British-run Northern Ireland in the European Union's customs union.

Merkel says for a deal to be agreed upon, Northern Ireland would have to stay in the EU customs union forever, which Johnson is not prepared to agree to.

A source at Downing Street has told the BBC that a Brexit deal is "essentially impossible" after Tuesday's phone call between the PM and Angela Merkel.

The German chancellor is the latest critic of Johnson's new plan unveiled last week.

Under the British plan, Northern Ireland would stay aligned with the EU single market regulations for goods, but stay in the UK customs zone, something the EU has long opposed.

Earlier on Tuesday, the European Council president Donald Tusk, accused Johnson of not taking the negotiations seriously enough and playing "some stupid blame game."