The Deputy Prime Minister will take part in events marking the 250th anniversary of US independence and will discuss the Ukraine peace process.
But the row over Greenland – an autonomous territory of Nato member Denmark – casts a shadow over relations between the US and Europe.
The White House said the “US military is always an option” to achieve Trump’s goal of taking over Greenland, which he wants because of its strategic Arctic location and mineral resources.
Prime Minister Keir Starmer on Tuesday joined Danish counterpart Mette Frederiksen and leaders from France, Germany, Italy, Poland and Spain in stressing that “Greenland belongs to its people”.
Prime Minister Sir Keir Starmer
They said: “It is for Denmark and Greenland, and them only, to decide on matters concerning Denmark and Greenland.”
The issue of Greenland was not highlighted by officials ahead of Lammy’s visit, but his presence in the US will be seen as an attempt by the UK to play a role in bridging the gap between Washington and a Europe nervous about American intentions.
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During his two-day visit Lammy, who was removed as foreign secretary last year but still maintains a presence on the international stage, will highlight the strength of the so-called “special relationship” with America, claiming the UK and the US are “working together to secure peace and stability across the globe”.
“Far from being an abstract idea, it is built through practical co-operation and shared purpose,” he will say.
“In defence and security. In the trade and investment that benefit us all. In working together to secure peace and stability across the globe.
US president Donald Trump
“And in our partnerships on emerging technologies and energy security, which will help shape the world in the decades to come.”
Lammy, who is also Justice Secretary, will meet US Supreme Justice Elena Kagan and members of Congress on Capitol Hill.
Following the Deputy Prime Minister’s visit to Washington DC he will travel to Toronto to gather vital information on how judge-alone trials operate in Ontario and what lessons could be learnt for his plan to restrict jury trials in England and Wales.