The format, which was developed in the second series, remains ostensibly unchanged, and the programme is again presented by Robert Llewellyn and Cathy Rogers (who is also the executive producer). 10 teams, comprising three friends and an expert of their choosing, will fight their way through various heats and rounds, through to the series final in programme nine. Programme 10 will involve a grand challenge between the winner of this series, and the winners of series two, The Megalomaniacs.

As well as the usual interesting array of team members, not all of whom come from engineering or mechanical backgrounds (for example, the team of psychiatrists in series two, and the vicars who will be appearing next week), this series also promises another run of fascinating trials – coming up will be challenges to build an aerial bomber, underwater chariot, windmill, missile launcher, bridging machine, steam car, and a giant mower. In the final the teams will attempt to build a fireboat, and in the grand challenge, they will be building dragsters.

In the first challenge of the series, the teams had to build demolition machines, which were then raced to demolish part of a disused power station which had been built to withstand blast forces. As ever, Scrapheap Challenge does the science and engineering extremely well; one of the real strengths of the programme. Both presenters develop good relationships with the team members, and watching the programme you can feel the sense of enjoyment, camaraderie, and semi-serious rivalry.

In good Scrapheap tradition, both teams take completely different approaches – one team developing an almost “medieval” type of battering ram, with few mechanical things to go wrong, but requiring a lot of brute force. The other team going for the highly engineered approach, building a “munching arm” via a complex system of hydraulics, which could either work brilliantly – or not at all. True to form, the final race was close, and nail-biting, with the complex machine working superbly, but sporadically. In the end, slow and steady, and brute force wins the day, but only just.

The series certainly seems to be gathering momentum, with the programme being shown in America, as Junkyard Wars, a video release, and suggestion on the website that there may be a fourth series. Long may it continue!

Scrapheap Challenge is an inspired piece of television. I’ve never met anybody else who watches it or has heard of it. And they do not know what they are missing.

In fairness, I only watched it the first time because it was presented by Robert Llewellyn (as a bit of a Red Dwarf fan I tuned in to see what he was like in it). Since that first episode I’ve been totally hooked. The premise is simple. Two teams, comprising three team members and a visiting expert, have to build working machines from junk they find in a scrapyard, in one day. At the end of the day there is some form of competition between the machines to determine the winner. In series one, which was simply called Scrapheap, we saw medieval siege engines, power pullers, underwater diving equipment, racing buggies, powerboats, and rockets. This series has gone on to even greater heights with flying machines, cannons, amphibious vehicles, land yachts, fuel-efficient vehicles and marine salvage machines. The final saw two teams building and racing vehicles without wheels, in what turned out to be a challenge that really upped the ante. Eventually it was the most nerve-racking decider, all the more remarkable for the fact that they were possibly the slowest machines ever seen on the programme.

The format has changed slightly since series one, but that is not to any detriment of the programme. Originally we met two regular teams who stayed with us throughout the series, and with whom you could take sides. We were introduced to characters you loved to love like Dick, the army major, a benevolent dictator with an incredible moustache; Dave, who just wanted to weld everything. There were also the characters you loved to hate, like Ann, the team captain who named machines after Terry Pratchett characters. This series had been a knockout challenge, giving us the opportunity to meet many more teams, without losing the opportunity to root for one side or the other.

Scrapheap Challenge really seems to meet it aims. It is described as a science programme, and it does present the science really well. The mechanics involved in all the projects is explained simply and clearly but without dumbing down, so you can see why some ideas will or won’t work and the risks the teams are taking in following certain approaches. Perhaps it is this understanding that makes the whole programme appealing. Although the final part is the most exciting, as the teams compete, just watching the process they went through is equally fascinating. As there are so many potential solutions to the problems they are presented with, inevitably both teams come up with very different machines, which makes the competition more exciting, as it is so difficult to predict the outcome.

Fair enough, you know that they get extra time occasionally, and some stuff is planted in the scrapyard to help them along. But it does not detract in any way from the programme – because you want to see the final challenge, the race, to see the machines work (or not!), and to (hopefully) see your team win fair and square. The outcome is never a certainty. Against form, in series two we have seen the navy team beaten when building an amphibious vehicle, and the army team beaten at building a cannon. The good news is that series three has been commissioned, and the hunt is on for new teams to take up the challenge. It can only be hoped that this programme, and the teams, carry on the good work, and that future challenges aspire to the words of the immortal Major Dick – “Death or Glory”.