A trip on the royal train by the Prince of Wales from Scotland to Yorkshire cost taxpayers more than £33,000, royal accounts showed.
The two-day journey saw Charles travel from Ayr to Yorkshire in September to carry out engagements including a visit to HMP Leeds and a community shop and pub, before he travelled on to Aberdeen. At £33,249, it was the most costly trip by royal train in 2015/16.
Other journeys by the royal family included a charter flight by the Duke and Duchess of Cambridge from Northolt to Dundee and then to Oxford, which cost £13,212.
Fifty-seven trips by the royals and their staff cost more than £10,000 each in 2015/16.
More than £500,000 was spent on helicopter flights, with 221 journeys coming to £569,483.
The Windsors’ total official travel costs were £4 million – £1.1 million less than the previous 12 months.
The most expensive trip – at nearly £100,000 – was by Charles and the Duchess of Cornwall when they flew by charter plane for an official visit to Croatia, Serbia, Montenegro and Kosovo. The flights cost £94,409.
Charles also took a charter flight costing £74,500 from Luton to Aberdeen, then to Istanbul and Canakkale in Turkey before returning to Aberdeen and Northolt, for the Gallipoli campaign centenary.
The Queen’s travel costs for a trip to Malta cost more than £64,000, while travel for her state visit to Germany came to more than £40,000.