World leaders and visiting royals could be made to travel to the Queen's funeral by BUS, with state cars banned by the government.
Leaked documents show that important mourners may be transported to the service by coach from a secret site in west London - but No10 today said US President Joe Biden will not be expected to travel this way.
VIPs have also been banned from taking helicopter flights around the UK and urged to take commercial flights into the country.
The government expects around 500 dignitaries from around the world to descend on the capital as the Queen is laid to rest - and has put a ban on entourages attending the historic service.
Officials face a massive headache cramming heads of state and royals from overseas into Westminster Abbey for Monday's service as hundreds of thousands line the streets of London.
A document leaked to Politico at the weekend said that escorted coaches will take them to the venue from an undisclosed location where they will have to leave their cars “because of tight security and road restrictions”.
Dignitaries were also advised that they will not be able to land private aircraft at Heathrow - instead telling them to go to "less busy" airports if they travel this way.
The Foreign, Commonwealth and Development Office (FCDO) papers state: “Multiple and comprehensive layers of security will be in place across London and at all the official venues used for the state funeral and associated events."
The UK will not consider requests by foreign government representatives for official meetings "because of the extensive ceremonial programme related to the state funeral", the FCDO warned.
Following the funeral service, powerful delegates will walk to a reception hosted by Foreign Secretary James Cleverly on the grounds of the abbey, it is understood.
Asked if US President Joe Biden will be expected to travel by bus, the Prime Minister's official spokesman said: “The arrangements for leaders and how they travel will vary depending on individual circumstances.
"Arrangements for different leaders will vary depending on things like security risks.”
On whether the US President would be expected to board a bus to the funeral, he said: “That would be a question for the US in how they prefer the president to travel and I think that’s fairly well documented.”
Those invited will only be allowed to bring their spouse into Westminster Abbey, which has a capacity of around 2,200.
An FCDO source said: “This is a huge scale operation with around 500 dignitaries from across the world expected and large public crowds already seen - with more likely on the day of the funeral.
“The logistics have been meticulously planned to try to make it as smooth as possible for those attending."
