Joe Biden may have to get the bus to the Queen's funeral

The White House confirmed that Mr Biden will attend the funeral, along with his wife Jill.

There is precedent for former US presidents to attend such an event, amid speculation that Donald Trump will not be invited.

Dignitaries will travel to Westminster Abbey in escorted coaches and “because of tight security and road restrictions” they will be required to leave their private state vehicles behind, according to leaked documents, seen by Politico.

The publication reported that a communication from the Foreign, Commonwealth and Development Office (FCDO) was sent to embassies late on Saturday.

The Department said it “regrets that, because of limited space at the state funeral service and associated events, no other members of the principal guest’s family, staff or entourage may be admitted,” it was reported.

According to the document, world leaders have also been urged to travel on commercial flights and have been told they cannot use helicopters to travel around the UK.

The Prime Minister’s official spokesman said that he wouldn’t comment on leaked documents, while the guest list for the event is a matter for the Palace.

“I would say that clearly arrangements for leaders including how they travel will vary depending on individual circumstances. And the guidance and information provided is guidance. But beyond that, I wouldn’t comment,” he said.

It comes as one person has already arrived to queue for the Queen’s lying in state in London – more than 48 hours before the line opens.

Infrastructure is being set up and security staff are preparing for millions of people to wait to pay their respects to the late monarch, whose coffin will be placed in Westminster Hall from 5pm on Wednesday until the morning of Monday September 19.

Vanessa Nathakumaran, 56, from Harrow, appeared at 12pm on Monday to the south of Lambeth bridge, where the entrance to the queue is expected to be set up.

Ms Nathakumaran, who is staying at a hotel in Lambeth so she does not miss the opportunity to pay her respects, told the PA news agency she began “admiring the royal family” from the age of 10 and has “a huge respect for them”.

Downing Street confirmed that in addition to the state funeral, the public will be invited to join in a minute’s silence the night before.

People are invited to mark the occasion privately at home, on their doorstep or street, or at community events and vigils, No 10 said.

Those living overseas are also encouraged to take part at 8pm their time.

Downing Street said the “shared national moment of reflection” will be an opportunity for everyone across the UK to mark the Queen’s death.

The spokesman also suggested commuters may want to “change their working patterns accordingly” as the capital will be “extremely busy” for the Queen’s lying in state.

In spite of the disruption to commuters in London, Downing Street confirmed that the Government still plans to set out further details of the energy package announced last week during a “fiscal event” later this month.

No date has yet been set for a fiscal event, amid the continuing cost-of-living crisis.

Ms Truss had announced last week long-awaited Government plans to tackle sky-high energy bills and ease the cost-of-living crisis, with a focus on capping prices and boosting domestic energy supplies.

The Government has a narrow window to schedule the fiscal event, with the Commons due to go into conference recess on September 22, but it is unclear when legislation will be debated.