He has converted both his Jag and his Land Rover to run on used cooking oil, installed a reed-bed sewage system for his country house and a roof-harvested rainwater irrigation system for the garden. During the past tax year, he financed a charity to teach tilework and other traditional Afghan crafts in Kabul; opened a bakery to produce organic Cornish pasties in Cornwall; and encouraged his staff to bicycle around London. He personally wrote 2,134 letters. His wife wrote 1,503. And together they wrote (signed) 53. This does not include his private and (theoretically) unpublishable scribblings. He is the last great letter writer left in our age of e-mails, voicemail and text messaging. He employs 130 people directly working for him, including two butlers, five orderlies and 1.5 valets for squeezing toothpaste and whatnot.

He is, of course, the Prince of Wales, the annual review of whose activities, income and official expenditure was published yesterday. Income more than £17.5 million, a healthy increase of £1.5 million over the previous year. After expenses were deducted, he paid 43 per cent tax, significantly more than the average private equity billionaire. He has taken to heart criticism of his hypocritical use of helicopters and jets. These calculations are inexact, but his carbon emissions fell by 9 per cent during the year. He is thus doing more and emitting less (except in tax).

His is an odd job. But who else would put up with having 632 official engagements in a year? Who else would have his or her finances so publicly scrutinised? He and his immediate family cost us each 4p a year. Despite teasing mockery, some of it ill-natured, this is real value for money.