The prospect of the US becoming a so-called "associate member" of the Commonwealth has been raised as the Royal Commonwealth Society makes plans to open a branch in the country.

Director of the society Michael Lake reportedly wrote a letter to the new Donald Trump-led US administration to gauge interest in the plan towards the end of last year.

The UK's pending exit from the European Union has been touted as an opportunity to reconnect with former Commonwealth nations as a way to boost trade.

"The UK rather left this treasure in the attic, and forgot about it because people were so glued to Brussels," said Michael Lake, the director of the Royal Commonwealth Society (RCS) said, according to the Telegraph.

The newspaper said that opening a RCS branch in the US would further Britain's ties stateside with the country now led by a president who has strong links with the UK via business investments and his Scottish mother.

Trump said his mother was a royalist and he is scheduled to meet the Queen later this year during a controversial state visit. Lake referred to the "opportunity of a new president, and the slightly dangerous but great fun opportunity that the 'Bad Boys of Brexit' offered".

The letter was apparently delivered by hand to the president's chief strategist Steve Bannon by former Ukip leader Nigel Farage, having been passed to him by aide Andrew Wigmore.

Lake believes that opening a Commonwealth branch in America was "mutually advantageous" and would help the UK and the US "find imaginative ways" to work together. Wigmore told the Telegraph that the response from the White House was "very positive".

But the Commonwealth is separate organisation to the RCS. A spokesperson told The Sun Online: "The Royal Commonwealth Society is an independent civil society organisation. While it may be interested in opening an RCS branch in the USA, this should not be confused with offering the USA membership in the Commonwealth.

"The Commonwealth is a voluntary association of independent and equal sovereign states. Commonwealth Heads of Government have agreed on criteria and a process for applying for Commonwealth membership.

"All member governments must reach consensus on admitting any new member. There is no 'associate' member state status in the Commonwealth."

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The US could become an 'associate member' of the Commonwealth Neil Hall/Reuters