Invitations to the Queen’s state funeral have not been sent to Russia, Belarus or Myanmar, while Iran will only be represented at an ambassadorial level, Whitehall sources have said.

The event will see around 500 dignitaries from around the world descend on London to pay their last respects to the long-reigning monarch.

They will join members of the royal family, UK prime ministers past and present, and key figures from public life at Westminster Abbey – the historic church which can hold around 2,000 people – at 11am next Monday.

“This is the biggest international event we have hosted in decades,” a Whitehall source said.

The source compared the logistical task to organising “hundreds of state visits” within a matter of days. Normally, there might only be two or three a year.

It presents a huge logistical, diplomatic and security challenge, with practice runs taking place in the dead of night.

Invitations were sent over the weekend to the heads of state of nations with which the UK has diplomatic relations. For most countries, that means the head of state plus one guest.

However, invites were not dispatched to the leaders of Russia – which is continuing its onslaught on Ukraine, Belarus – which has supported its neighbour in the invasion, and Myanmar – where the military seized power in a coup last year.

No guest list has been published yet, but US President Joe Biden was among the first to declare he will be flying in with his wife, Jill.

The leaders of most Commonwealth countries are expected to attend, with New Zealand Prime Minister Jacinda Ardern saying she will make the nearly 24-hour journey with a delegation of five others.

Her Canadian and Australian counterparts, Justin Trudeau and Anthony Albanese, have also confirmed their presence.

Mr Albanese announced that he will not be travelling alone, tweeting that at Buckingham Palace’s invitation, he and Governor-General David Hurley will be accompanied by “10 Australians who have made extraordinary contributions to their communities”.

France’s Emmanuel Macron, Germany’s Frank-Walter Steinmeier, Italy’s Sergio Mattarella, Turkey’s Recep Tayyip Erdogan and Brazil’s Jair Bolsonaro are among the presidents attending, along with the European Commission’s Ursula von der Leyen.

King Felipe of Spain and his wife, Queen Letizia, are among the European royals who will attend.

Emperor Naruhito of Japan is also expected to travel to London in what would be his first overseas trip since ascending the throne in 2019.

The guest list for the Duke of Edinburgh’s memorial service could provide an idea of who else might come. The 1,800-strong congregation featured around 30 foreign royals, including Prince Albert of Monaco, Denmark’s Queen Margrethe, and King Harald and Queen Sonja of Norway.

But it is not thought the trip will be made by Ukrainian President Volodymyr Zelensky, who took time out from organising his country’s fightback against Russian President Vladimir Putin’s forces to sign a book of condolence for the Queen.

Arrival times will vary from leader to leader, Downing Street said.

Liz Truss is not expected to hold any “formal” bilateral meetings with world leaders during the mourning period, but “there may be informal conversations that take place”, the Prime Minister’s official spokesperson said.

Former Tory leader Lord Hague said that while there will “of course” be diplomacy surrounding the funeral, that is not the main focus.

“Of course there is some diplomacy – you can’t have that number of people together from around the world without them starting to say ‘Well, what do you think is happening in Ukraine?’,” he told Times Radio.

“Nevertheless, they’re coming because they want to pay their respects to this extraordinary head of state. And that is what 90% of it will be about.”

Downing Street on Monday refused to comment on reports that world leaders visiting London for the Queen’s funeral have been asked to travel on commercial flights and will be bussed to Westminster Abbey.

“Arrangements for leaders, including how they travel, will vary depending on individual circumstances,” the spokesman said, adding that “the guidance and information provided is guidance”.

Mr Biden is understood to have dispensation to use the heavily armoured presidential car known as the Beast, while most other leaders will have to take a shared coach to the Abbey from west London.

The Queen will lie in state in Westminster Hall from Wednesday to Monday, when her coffin will be taken in procession from the Palace of Westminster to Westminster Abbey for the funeral service.

Hundreds of thousands of people are expected to line the streets of the capital during the funeral.