It ended as a launch pad for the Duke and Duchess of Sussex’s road to freedom, with a bombshell statement decrying the tabloid media, an announcement the Duchess had filed a lawsuit, and television interviews laying bare their unhappiness.

The cost to the public purse? Now revealed as a quarter of a million pounds.

The Duke and Duchess’s tour to South Africa, Angola, Malawi and Botswana cost the taxpayer nearly £245,643, accounts have disclosed, making it the most expensive journey for the Royal Family in 2019-2020.

It came just months before the Sussexes left the working royal family in pursuit of personal and financial freedom.

A senior royal source insisted the couple are under no obligation to pay money back for the trip, saying it was a key visit approved by the Foreign Office and successful in helping to highlight the work of numerous charities.

"The Duke and Duchess of Sussex undertook over 20 engagements, bringing attention to a number of worthwhile causes, in particular, raising awareness of the work and the legacy of the Halo Trust," the source said.

"So, the visit, as an official visit funded by the Government, fulfilled the objectives that were set out for it and so therefore there would be no requirement or obligation on the Duke and Duchess of Sussex to make any payments in relation to that official visit."

Buckingham Palace declined to confirm arrangements for the refurbishment cost of Frogmore Cottage, on which the couple will now pay commercial rent, saying it had to be agreed by the National Audit Office before appearing in next year’s accounts.

The Prince of Wales’ accounts, which related to his private income from the Duchy of Cornwall rather than taxpayers’ money, showed a half-a-million-pound rise in expenditure for activities including the funding of his children.

The funding area described as covering the Duke and Duchess of Cambridge, the Duke and Duchess of Sussex and “other expenditure including capital expenditure and transfer to reserves” rose to £5,607,000 from £5,051,000 last year.

The Sovereign Grant report, published today, comes as the Duke and Duchess of Sussex made headlines for their US presidential election voting registration campaign.

In a video message, the Duchess called the election “the most important of our lifetime” and the Duke urged Americans to “reject hate speech, misinformation, and online negativity”.

Asked about their intervention, President Trump said: “I’m not a fan of hers and I would say this, and she probably has heard that.

“But I wish a lot of luck to Harry, because he’s going to need it.”

Buckingham Palace has already distanced itself from the Sussexes' remarks, saying the Duke was speaking in a personal capacity in what appeared to be an attempt to smooth diplomatic relations.

On Thursday, the Duchess continued her new life of freedom in the US by sending a message to America’s Got Talent, in support of 59-year-old singer Archie Williams, who was wrongfully imprisoned for 36 years before appearing as a contestant on the show.

No one, not even @Archieisfree, expected a special message from Meghan Markle, Duchess of Sussex! pic.twitter.com/qng1YTD0q9

— America’s Got Talent (@AGT) September 24, 2020

The Sovereign Grant report for the last financial year also included other costly overseas trips by members of the royal family.

A charter flight for the Duke of York to attend the Royal Portrush Golf Club's Open championship in Northern Ireland cost £15,848.

The Duke stepped back from royal duties several months later in disgrace following a Newsnight interview about his involvement with Jeffrey Epstein.

The royal source defended Andrew's use of a charter instead of a scheduled flight, saying: "In this particular case, we concluded that actually, the use of charter was the only way to get him to complete his engagements to fit in with his other programmes."

A two-day visit by the Prince of Wales to Oman to pay his condolences following the death of Sultan Qaboos bin Said cost £210,345, said to be because the trip was taken at very short notice and there were no commercial flights available.

The Prince’s flight from Brize Norton to Aberdeen on March 22, shortly before he tested positive for Covid-19, cost £19,100.

Sir Michael Stevens, Keeper of the Privy Purse, said the next few years will bring “financial challenges” as a result of the Covid-19 pandemic, with current forecasts of “reduced growth” in the Sovereign Grant.

He estimated there will be more than £20million shortfall in the £369m budget agreed for the major works reservicing Buckingham Palace, with £5m a year lost in income from the Royal Collection Trust.

“In responding to both these financial challenges we have no intention of asking for extra funding and will look to manage the impact through our own efforts and efficiencies,” he said.

Accounts for the Sovereign Grant have shown the monarchy cost the taxpayer £69.4 million during 2019-20-an increase of 2.4 million on the previous financial year.

All major expenditure areas have increased, from payroll, up £1.2 million to £24.4 million, to travel, rising by £700,000 to £5.3 million, and housekeeping and hospitality, rising by £300,000 to £2.6 million.