The Prime Minister has said the UK will “continue to bring maximum pressure to bear” on Russia as he pledged that Vladimir Putin would “feel the consequences” for invading Ukraine.

On the eve of his trip on Tuesday to Poland and Estonia, Boris Johnson said international leaders were united in agreeing that the Russian president “must fail” after his decision to send troops into the neighbouring country.

Mr Johnson is due to meet with Warsaw and Tallinn leaders and visit British troops serving in Estonia, which shares a border with Russia.

We speak with one voice when we say, Putin must fail

Speaking before his visit to the two eastern European members of Nato, the Prime Minister said: “Today I will visit Poland and Estonia, two countries that are acutely affected by the current crisis in Ukraine.

“We have shared values that are more important than ever to protect, as the humanitarian situation gets worse.

“Alongside all our international allies the UK will continue to bring maximum pressure to bear on Putin’s regime to ensure he feels the consequences of his actions in Ukraine.

“We speak with one voice when we say, Putin must fail.”

Officials said Mr Johnson will meet Polish Prime Minister Mateusz Morawiecki to underpin the UK’s financial and diplomatic support for central Europe as it faces the prospect of a humanitarian crisis, with Ukrainian refugees continuing to head for the Polish border.

The Prime Minister will then travel on to Estonia, where he will speak with Nato secretary general Jens Stoltenberg.

They will jointly visit British troops serving “on the front line of Russian aggression” in Tapa, No 10 officials said.

Mr Johnson will also meet Estonian Prime Minister Kaja Kallas and Estonian President Alar Karis to discuss European security and stability.

The trip comes after Poland and Romania joined a G7, European Union and Nato leaders’ phone call on Monday to discuss the crisis in Ukraine.

Downing Street said the leaders “agreed to pursue every avenue to ensure that Putin fails in his ambitions”.

During the call, Mr Johnson stressed the need for allies to continue to provide Kyiv with defensive weapons and the requirement to support Ukraine’s neighbours, which include Poland, in dealing with “large numbers of Ukrainians escaping violence in the country”.