Since I set up these pages in 2003 they have been read by tens of thousands of people all over the world. Many hundreds of readers have publically commented on the pages, through Internet discussion forums, blogs, etc. The vast majority of these comments have been supportive of my work and views, and this positive feedback has been helpful in persuading me to carry on. But a small number of people have been critical, either of specific comments or indeed of the whole thrust of the site. Now, since I believe in free speech, in one sense I can hardly complain about this. I would however ask that critics take a minute to read this page before expressing their critical comments in public.

Firstly, I positively welcome constructive criticism. I am very grateful to the people, both independent readers and makers of devices, who have written to point out minor errors and opportunities for improvement. This kind of proof-reading helps me to develop the site so it can be as useful a resource as possible - so if you think you've found a technical error, a broken link or even poor English, don't just post your comment on a Forum where I may never see it, instead email me - I will always consider your views carefully and reply.

But before you do, please make sure your criticism isn't already adressed somewhere on this site:

If you disagree with my views on a particular fuel "saving" product, make sure you have read the general comments about such products as well, as this page gives a lot more background about the technical and commercial reasons to be sceptical.

If you think I have no right to express these views at all, check my morals page. If you think I'm in the pay of the oil companies, read what I say about conspiracy theories.

But far and away the most common criticism goes along these lines: I fitted the SuperFuelMiser3000 to my car, and now my economy is 10% better and the car feels faster. Mr Fuelsaving has never even seen the SuperFuelMiser3000, yet he says it doesn't work. He is obviously just talking nonsense.

My basic reasoning is explained here, but since this view is expressed so often, here's a summary:

• While I have not tested the specific device mentioned, in most cases I have tested the general principle by which it supposedly works, and/or there is good test data to prove that a very similar device under a different name does not work. Therefore, it's highly likely that the SuperFuelMiser3000 doesn't work either

• Any economy or performance data measured on the road is affected by so many confounding factors (traffic, type of journey, driving style, weather, etc) that it's impossible to say if the improvement you have measured is really due to the device or not. Even worse, you have probably subconsciously altered your driving style since fitting the device, since you are keen to see it work. There are many examples of users reporting great on-road results from a fuel "saving" device, followed by scientific testing proving the true benefit is vanishingly small (see here for more comments on this). So your apparent improvement really doesn't prove anything

• For the same reason, it is pointless me fitting one to my car and testing it on the road. A change in economy of (say) 10% due to a fuel "saving" device would be completely lost in the "noise" of normal variability. The only way I could meaningfully test a device would be to do some proper drive-cycle measurements, but these are far too expensive for me to do (5 - 10 000 pounds)

• Crucially, the company selling the SuperFuelMiser3000 could afford to do this testing, and yet they haven't, even though this kind of incontrovertible proof would massivly increase sales. Could this be because they know scientific testing will prove it doesn't work?

If you're still not satisfied, please email me with your query and I will do my best to answer it. And if after all that, you still think I'm wrong, then of course feel free to say so on discussion forums etc, though I would appreciate you sending me a link to the discussion so I could take part in the debate.