THE brief splash of sunshine that counted for summer recently had company car drivers throughout the country reaching for one of the increasingly 'must-have' gadgets in their cars – air conditioning.

But although drivers can cool down at the touch of a button, they can also get the fleet manager hot under the collar, as the extra power needed to cool the cabin means the car drinks more fuel.

Take our long-term Ford Mondeo TDCi, which I recently took on a marathon drive into the heart of France for a fortnight.

With a baby aboard, keeping the car cool was vital, so as the temperature soared to 35 degrees centigrade, the air conditioning was turned to maximum whenever we were in the car. As a result, although the car's average fuel consumption has reached as high as 43mpg on some occasions, it plummeted to 38mpg, thanks to town driving and demand for lots of cool air.

In more than 1,000 miles of motoring, the engine proved a delight, offering plenty of power, but whisper quiet during the long cruise to our holiday destination.

Despite our confidence that the Mondeo could easily swallow the luggage of two adults and a baby, we underestimated just how much space a pram, travel cot, five packets of nappies, food box, clothes, changing bag etc would take. We just managed it, but I wouldn't bet on some of its rivals achieving the same result.

Reliability from the Mondeo had been excellent, but at UK Customs on our return, when the button was pressed, the driver's window disappeared into the bodywork never to return.

Apparently a very small holding screw has broken and is easy to fix, but it is a dealership job. I am just thankful it held out until we reached the UK.