An Australian cannot be our head of state. But we do have a role in vice-regal affairs; we pick up the bill when the head of state’s family comes to visit.

The media has reported with delight the news that Prince William, Kate Middleton and boy George will tour Australia next month. What didn’t feature in those stories is that by custom Australian taxpayers pay for it all — and Crikey estimates the 10-day trip will come in at $2 million or more.

No expense has been spared. The royals will be accompanied by an entourage of 11 people, including Kate’s hairdresser, three press officers, an orderly and a nanny. The group of 14 will be ferried to and around Australia by special air force jets. So when they pop from Sydney to Brisbane for the day, an RAAF plane will take them there, wait, and bring them back again. The royals will not take any commercial flights, except for the flight back to London.

Will and Co will stay in official vice-regal mansions in Sydney and Canberra, and in commercial accommodation near Uluru. Official receptions have been organised around the country (see the itinerary here).

The royals will tour four cities (Sydney, Brisbane, Adelaide and Canberra) plus Uluru and the Blue Mountains from April 16. That means at least seven RAAF flights with a total flying time of 16 hours. Based on estimates of the cost of chartering a RAAF jet, at $17,000 per hour of flying time, Crikey calculates the royal party’s flights alone will cost the Australian taxpayer at least $272,000.

When British royals come on official visits the federal government pays for flights, accommodation, meals, phone calls, minibar bills, and even the presents the royals give out (which can cost $15,000). State governments cough up, too. Organising a day trip for a royal can cost $100,000 an hour, e.g. when Queen Elizabeth visited Melbourne in 2011.

The British royals have been availing themselves of free Australian hospitality with enthusiasm. Since 2005 (and including the upcoming April visit), 10 British royals have visited: Queen Elizabeth, Prince Philip, Princess Anne, Prince Edward, Charles, Camilla, William, Harry, Kate and George. It’s been estimated each trip cost between $350,000 and $1.8 million.

So what will the upcoming trip cost? It’s hard to say because details are kept quiet. The federal Department of Prime Minister and Cabinet pays the bills, and its Ceremonial and Hospitality Branch (CERHOS, that is) is in charge of the details. Crikey asked PM&C what the cost estimate of the upcoming visit was, but they wouldn’t say. “[W]hen all costs for the visit have been fully acquitted, the details of those costs are made available to Parliament,” a spokesperson said.

So we turned to budget estimates hearings for previous royal visits. Queen Elizabeth visited Australia for five days in 2006 with Prince Philip, taking in Melbourne, Canberra and Sydney. A 2007 estimates hearing heard that cost the federal government $1.8 million (excluding state government contributions). The federal cost was so high it blew the “state occasions and official visits” budget. Frank Leverett from CERHOS told the 2007 hearing:

“Royal visits are always a high-expenditure item. The total was not significantly different from any other visit …”

There’s another clue in the Queen’s most recent visit, in October 2011 (10 days with Prince Philip). In the revised PM&C budget for 2011-12, “state occasions and official visits” were unusually high at $5.85 million. The estimated cost over the forward estimates averaged $3.41 million, so something cost an extra $2.44 million. We don’t know how much of it paid for the Queen’s visit, but it’s fair to assume some did.

Given the upcoming royal visit by Will and Kate is twice as long as the Queen’s $1.8 million 2006 trip, will visit more places, and is in 2014 dollars (not 2006), it can be estimated the cost of the trip will be at least $2 million. It’s possible the federal government’s share will be less, and the state governments’ share more, than the Queen’s 2006 visit.

It’s unlikely taxpayers will ever know the full cost of Will and Kate’s visit as no one seems to have added up federal and state bills for previous royal visits (and governments make it hard to do so). The high cost of RAAF flights may be cleaved off to a different section of the budget, as with running the Governor-General’s residences for the royals.

Republican Greg Barns, who directed the Australian Republican Movement’s failed 1999 referendum campaign, says Australians should not pay for royal visits. “These are expensive holidays that are borne by the Australian taxpayer,” Barns told Crikey.

On the royal family, he said: “To the extent that they represent anyone, they represent the United Kingdom. It’s a very expensive exercise in letting us all know that no Australian can be head of state.”

Barns says it’s appropriate for the government to pay for state visits by government leaders heading up diplomatic and trade missions because there is an economic gain to Australia — trade deals might be advanced and market access promoted. But the British royals are “simply flying the Buckingham Palace flag”.

“They ought to pay for it. They’re hardly over-taxed. The royal household is worth billions,” Barns said.

But Dr David Beirman — a senior lecturer in tourism at the University of Technology, Sydney with 30 years’ experience in the travel industry — says paying for the royal visit could be an excellent investment, encouraging high-end British tourists to visit. “The very presence of Will and Kate makes Australia very fashionable as a destination,” Beirman told Crikey.

Magazines like Tatler and Hello will cover the trip, and dozens of journalists will accompany the royals — a boon for Tourism Australia. The royals are due to engage in photogenic activities like visiting bilbies at Taronga Zoo, lifesavers at Sydney’s Manly Beach, and Uluru. Beirman says many British tourists already visit Australia, and with the UK economy recovering somewhat and the Aussie dollar dropping in value, the time is ripe to promote tourism.