Andrew Mountbatten-Windsor accumulated more than £2million in taxpayer-funded expenses during his last four years serving as the UK's trade envoy, newly revealed figures show.
The former working royal's annual costs jumped by 15 per cent in a single year, climbing from £561,325 to £649,044 after he secured additional Government funding.
This increase came despite consultants having previously identified potential savings following a review he himself had commissioned in 2008.
The i Paper calculated the total expenditure at £2,172,122 by combining records from both royal travel accounts and the now-defunct UK Trade & Investment agency.
However, the actual sum is likely higher still, as royal accounts only recorded individual journeys exceeding £10,000.
Mr Mountbatten-Windsor received no salary for the envoy position but had all travel and accommodation covered by public funds.
His most costly single journey totalled £194,951 for a 13-day expedition through central Asia and China in October 2008.
Flight expenses alone reached £121,810 for an 11-day tour encompassing Rome, Milan and Almaty in Kazakhstan.
A chartered aircraft carried him to the Egyptian resort of Sharm el-Sheikh for just one day to co-chair the World Economic Forum, costing £55,269.
More than half of his 36 trips during this period exceeded £50,000 each, with 19 surpassing that threshold.
Visits to China alone accounted for nearly £400,000 across the four years.
Mr Mountbatten-Windsor continued claiming expenses totalling £286,301 after announcing his resignation in July 2011 amid scrutiny over his friendship with convicted paedophile Jeffrey Epstein.
He undertook six further international visits to destinations including Saudi Arabia, Singapore and Thailand before finally departing the role in spring 2012.
William Yarwood, campaigns director at the TaxPayers' Alliance, condemned the revelations, telling The i Paper: "Taxpayers will be appalled that Andrew Mountbatten-Windsor's trade envoy expenses ran to more than £2m, and the true cost is likely even higher once smaller travel costs and inflation are taken into account."
He added: "These eye-watering bills show why transparency over taxpayer-funded royal duties should never have been optional."
Graham Smith, chief executive of the anti-monarchy organisation Republic, labelled the figures "staggering" and demanded "full disclosure and an inquiry into royal costs and expenses".
Mr Smith argued the position had always prioritised "royal status rather than achieving anything significant for the UK", adding: "These figures add to the impression the royals exploit these opportunities to live the jetset lifestyle at taxpayers expense."
Buckingham Palace declined to comment on the figures, stating it no longer represents the former prince. GB News has contacted Mr Mountbatten-Windsor for comment.
The 66-year-old was arrested in February on suspicion of misconduct in public office after emails from the Epstein files appeared to show him sharing confidential documents with the convicted financier during his time as trade envoy.
He has repeatedly denied any wrongdoing.
A Government spokesman confirmed full cooperation with the ongoing Thames Valley Police investigation, emphasising that "no one is above the law, and all allegations are taken seriously".
The spokesman noted that the role Mr Mountbatten-Windsor held differed significantly from modern trade envoy positions, which are now filled by unpaid parliamentarians appointed by ministers and bound by formalised conduct rules.
Our Standards: The GB News Editorial Charter