A senior aide to Donald Trump held secret talks with Brexiteers during a visit to London last week, it emerged today.

National Security Adviser John Bolton spent more than an hour with the influential European Research Group of backbench Tory Brexiteers.

Downing Street was not told about the meeting in advance sparking fury in Whitehall.

It has raised fears the US President could also meet with Brexiteers during his visit to Britain later this month in defiance of diplomatic protocol.

National Security Adviser John Bolton (pictured in Moscow last week) spent more than an hour with the influential European Research Group of backbench Tory Brexiteers

Veteran Tory MP Sir Bill Cash (file image) was among members of the ERG who took part in the secret talks

Mr Bolton used his meeting to stress Mr Trump's continued support for Brexit, today's Sunday Telegraph revealed.

He also met with Theresa May's National Security Adviser Sir Mark Sedwill during the official part of his trip.

Veteran Tory MP Sir Bill Cash was among members of the ERG who took part in the secret talks.

Sir Bill said Mr Bolton 'gave a positive view of what he believed the president thought about Brexit'.

He told the newspaper: 'In advance of the president's visit there were some positive things said about potential trade deals.'

The US Ambassador has confirmed Donald Trump will meet the Queen during his visit next month.

The president is due to visit the country for the first time since being elected in 2016 on Friday, July 13.

It has raised fears the US President (pictured at the White House on Friday) could also meet with Brexiteers during his visit to Britain later this month in defiance of diplomatic protocol.

His trip was downgraded from a state visit to a working visit by Theresa May last year amid fears of mass protests.

But this afternoon ambassador Robert Wood Johnson told Sky News while plans have not yet been finalised, they will involve the president meeting Her Majesty.

There has been widespread speculation about whether or not he would meet the Queen however it has been confirmed today he will visit Windsor.

If the monarch was to snub Trump it would break tradition as the Queen has met every US president since 1945 bar Lyndon Johnson.

Last month it was reported plans were underway to close Windsor Castle on July 13 for a possible meeting between the two.

Insiders said holding a summit in Windsor would add weight to reports Theresa May plans to keep Trump's visit outside of London in a bid to avoid protests.