Has it become more difficult to shift used 4x4s lately? Perhaps it hasn’t just yet, but we could be reaching a point where the SUV is beginning to lose some of its traditional desirability.

First of all there is the much publicized (and ill-informed) anti-4x4 campaign where spokespeople claim the vehicles are unsafe and cause high levels of pollution.

One of my colleagues who writes in a national newspaper recently revealed to me that his paper receives hate mail whenever the motoring section tests a 4x4.

And politicians seem keen to talk tough on 4x4s with the threats of implausibly high tax levies However, I suspect this has a limited effect on sales as the campaign seems to be focused on London.

There are also reports that people are buying four-wheel drive vehicles in such numbers that used values will inevitably fall. The fact that more manufacturers are producing 4x4s means that at some point consumer appetite for SUVs will be sated.

We are also seeing vehicles that seem to mimic the styling of 4x4s, but have little, if any, off-road ability, and many don’t even have four-wheel drive.

It is difficult to assess at the moment the extent to which this could be happening, as many popular 4x4s have reached or are reaching the end of a model cycle.

The Land Rover Discovery3 is still quite new, the Mercedes-Benz M-class was changed last year, the new Rav4 arrived earlier this year, the XC90 has just undergone a revision, and a new Freelander, Honda CR-V and BMW X5 are around the corner.

Drops in part exchange values by a hundred pounds or so that we have noted compared with 12 months ago, could be down to ageing products. Then again, it could herald a turning point in the market when buying habits are beginning to change.