The new charter "encompasses science, technology and trade" and "underscores our joint commitment to NATO," Johnson said.

But while keen to affirm the strength of the long-celebrated partnership, Biden has reportedly ordered US diplomats to scold Johnson over his handling of Brexit and its effects on the Northern Ireland peace process.

The Times daily reported America's most senior diplomat in Britain, Yael Lempert, told Brexit minister Lord Frost that the UK government was "'inflaming' tensions in Ireland and Europe with its opposition to checks at ports in the province".

Port checks on deliveries heading into Northern Ireland from mainland Great Britain were agreed as part of the Brexit deal but caused consternation among unionist communities, who say it changes their place within the wider UK.

London suspended checks earlier this year because of threats to port staff, and the protocol has been blamed for the worst violence in years in the British-run province.

Talks to resolve the simmering border row broke up without agreement, and the European Union has threatened the UK with retaliatory action if it refuses to implement post-Brexit trading arrangements in Northern Ireland.

For its part, the State Department said the US will encourage both sides "to prioritise economic and political stability in Northern Ireland and to negotiate within existing mechanisms when those differences arise".

After talks with Johnson, Biden will attend the G7 gathering in a Cornish seaside resort from Friday to Sunday, alongside the British PM and leaders of Canada, France, Germany, Italy and Japan.

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