Donald Trump is on course to win re-election in 2020, senior British diplomats believe, as he approaches his first full year in office.

They think that despite a string of negative headlines the US president has largely kept his support base onside since entering White House

Possible Democratic contenders are seen as either too old – such as Bernie Sanders and Joe Biden – or lacking in the name recognition needed to defeat Mr Trump.

There is also a belief the US president has curbed some of his most radical policy instincts since taking office, such as ignoring Nato or pulling out of Afghanistan.

The analysis is significant as it underpins the advice Theresa May is given and shapes how she approaches the UK-US “special relationship”.

Should Mr Trump’s presidency look set to stretch to 2024, the Prime Minister could be more inclined to turn a blind eye to potential rows over his tweeting.