Motorway services rip us off 365 days a year - but I always find myself feeling most aggrieved by the scale of their rapacity in the festive season.
It was brought home to me last week by a stop at Chieveley Services on the M4. The logistics of doing a job meant that we had to leave one car here and pick up another, pop to Wales for a video shoot and then do the whole car-swapping process in reverse.
So guess how much Moto charges to leave a car for seven hours in a carpark in rural Berkshire? £5? £8?
No, try £25. Which, to apply some perspective, is slightly more than it costs to spend a day in long-term parking at Heathrow Airport.
My immediate reaction consisted of two words, the first was 'thieving' and the second was unprintable. But with two cars and only one of me, I had no choice but to pay up.
The thing is, it doesn't need to be this unpleasant. Existing motorway services are operated by private companies - but the service areas themselves are mostly owned by the Government and then leased out.
So why not end the current monopoly situation, where the operators basically charge their captive audience what they think they can get away with? Why not introduce some competition, and allow different businesses to operate on the same site?
Just imagine: a choice of restaurants, maybe even including one that doesn't fry everything. Or shops that charge high street prices, cash machines that don't demand £2.50 to deliver your own money and car parks that you can actually park in.
Who knows - if new style services actually proved popular enough then the total rental income from a site might well be more than that from one of the current, no-alternative monopolies.
If the Department for Transport wants to give Britain's beleaguered motorists a well-deserved Christmas present, it would be an excellent place to start.