By Deborah Haynes, security and defence editor

The Baltic states are “very unhappy” after the UK failed to invite their leaders to join a summit on Ukraine this weekend, a European diplomatic source has said.

The source, with knowledge of the situation, warned that Moscow would notice with interest that Latvia, Lithuania and Estonia have been excluded.

“Russia and our publics will clearly assess this that we are sold out by the US, but also by UK and France,” said the source, who spoke on condition of anonymity.

Sir Keir Starmer, fresh back from a friendly meeting with Donald Trump in Washington, is due to host the leaders of more than a dozen European countries for a summit in the UK on Sunday to discuss Russia’s war in Ukraine and wider European security.

Volodymyr Zelenskyy, who is holding talks with the American commander in chief at the White House on Friday, is also due to attend.

The diplomatic source confirmed Starmer would have a phone call with the leaders of the Baltic states – but signalled that this was a poor substitute for not participating in the summit, which will take place in person.

“We are truly very unhappy with a refusal to invite the Baltic leaders,” the source said.

The three Baltic countries – located on NATO’s eastern flank with Russia – are among the highest defence spenders in NATO as a percentage of GDP. 

They are also, relative to their small size, among the biggest supporters of Ukraine – giving weapons and funding to help the Ukrainian armed forces fight off Russia’s invasion – and have been the strongest voices in Europe raising the alarm about the threat posed by Vladimir Putin for years.

The aims of Starmer’s summit

The source said France was helping to organise the summit with Downing Street. 

It will be used to discuss support for Ukraine, including a plan to create an international “reassurance” force that could be deployed to the country to help secure a ceasefire if the US can negotiate a ceasefire deal between Kyiv and Moscow. 

Wider European security will also be discussed after Trump made clear that European NATO allies need to take a much greater responsibility for their own security instead of relying on the powerful US military.

The source added the leaders of Norway, Finland, Sweden and Poland were among the invitees, noting that Helsinki and Warsaw have both publicly ruled out contributing troops to an international security force in Ukraine.

‘Shameful’ to ignore key partners who ‘have a plan’

The source said members of the Baltic states “have a plan… but not invited”.

“All three Balts are among the highest supporters for Ukraine in terms of percentage of GDP and capabilities provided,” the source said.

“All decisions directly impact our security. Like another pact to divide Europe or take us for granted. Shameful.”

The UK regards Latvia, Lithuania and Estonia as key partners.

The three Baltic states are closely allied with Britain as members of the Joint Expeditionary Force, a grouping of like-minded European NATO member states.

Downing Street was approached with a request for comment.