While the motor and aviation industries have made great strides to improve fuel efficiency in recent years, train designers have been left behind.

Professor Roger Kemp, who led the study at Lancaster University's department of engineering, said trains were getting heavier, with more customer-friendly features but fewer seats. Virgin's SuperVoyager rolling stock is estimated to be 40 per cent heavier per seat than the ageing 125s they are replacing.

The study used computers to compare the amount of fuel used per seat for a family of four making a 400-mile journey from London to Edinburgh.

Driving a Volkswagen Passat 1.9-litre turbo-diesel on motorway and A-roads, the family would average around 60 miles to the gallon and therefore use 6.6 gallons - 30 litres - of fuel. That works out at 1.65 gallons or 7.5 litres per seat. By rail, they would use up 2.5 gallons - 11.5 litres - per seat.

The East Coast Main Line is electrified so the fuel figure given is the equivalent amount needed at the power station to generate the necessary electric current. The car's superiority increases dramatically when train speeds in excess of 200mph are considered.

Professor Kemp said: "The motor industry has made great strides in improving fuel efficiency and the environmental impact of its cars. The rail industry has simply not kept pace. The new trains are heavier and often have fewer seats. Sometimes, for health and safety reasons, there are no-go areas near the crumple-zones at the front, which reduces the average number of passengers. Some have very large disabled toilet areas - very nice, but it takes up seat space."

If trains are to retrieve their green credentials, they should be longer with more seats and keep their top speed to around 125mph, said Professor Kemp.

Roger Ford, of Modern Railways Magazine, said: "I know this will generate howls of protest, but a family of four going by car is about as environmentally friendly as you can get."

Tory transport spokesman Damian Green said: "This report will do little to encourage drivers to use public transport instead of the car. It is yet more evidence that the Government should end its war on drivers. So far, they have failed to encourage greener driving and instead have focused on taxing drivers out of their cars. I hope that the Government takes this report seriously."
 

Mr Brunstrom has a colourful description of his critics. They are the "petrolheads", led by Jeremy Clarkson, who like nothing better than roaring around our roads threatening carnage on a scale not seen since the Somme. Ministers are so afraid of this small and vocal group that they have been unwilling to make the case for cameras more strongly. The vast majority of people, he claims, support the use of speed cameras.

It is disturbing to discover that somebody such as Mr Brunstrom can get it so wrong. The anger against speed cameras is not from testosterone-fuelled road hogs (Mr Clarkson excepted) who like burning rubber. On the contrary, most people want nothing more than a police clampdown on boy racers and joy-riding twockers (so-called because they take cars without owners' consent). Anybody driving a stolen car, or with no fixed address, does not fear the flash of a camera. For them it just adds to the fun.

The people who really dread the cameras are largely law-abiding motorists who accidentally slip over the speed limit, often because they are on an unfamiliar road. An ICM poll earlier this year showed that while 38% of people think speed cameras make Britain's roads safer, 51% believe they are there purely to raise revenue. And these demands for money come with a summary form of justice -- a curt letter, threatening to use all the majesty of the law if you don't pay the £60 fine by yesterday, plus three points on your licence. The financial pain does not end there. Those three points can mean a whopping 20% on a driver’s insurance premium.

Bit by bit, motorists are being made "mad as hell", like the driver called D-Fens after his numberplate in the film Falling Down. He went berserk in a Californian traffic jam. It is not just the anger generated by the belief that cameras, while nabbing some genuinely dangerous drivers, also catch many who have driven safely for years. Before a driver ever gets to a highway he or she has to bypass an obstacle course of speed bumps, overzealous traffic wardens and astronomical parking, clamping and congestion charges. Drivers are branded as polluters, although a new study shows that trains are dirtier per passenger. The generally law-abiding motorist feels like a hunted animal. And this is not a minority. There are nearly 25m cars on British roads. Most of us drive or are driven. But the debate, far from being dominated by petrolheads, is driven by a few hardline policemen and cycle-riding zealots.

Speed cameras do save lives. Many who have lost relatives in road accidents know to their cost that speed kills. The government's own research suggests that cameras save 100 lives a year. But its figures also show that road deaths are down by a mere 2% since its baseline 1994-98 period, during which time car safety has improved. Deaths are down much more sharply in EU countries that have not used cameras. Cameras have a role to play at accident blackspots and at certain times.

But no policeman, or transport minister, should be happy with their indiscriminate use. Good policing requires discretion. Automatic fines generated by speed cameras merely generate deep resentment of the police among a group of people who would nornmally support them. That is something nobody wants. The government should reject Mr Brunstrom’s call. Like D-Fens we "can't take it any longer".
 

He launched an attack on Jeremy Clarkson, the Sunday Times columnist, accusing him and the "petrolhead lobby" of blinding the government to the benefits of the cameras.

It was Brunstrom, the chief constable of North Wales, who two years ago was forced to announce that cameras would be painted yellow and made more visible. Yesterday he announced it was time for a rethink. He said the decision to paint them yellow had been a political one because ministers were worried that the public would not support hidden cameras.

Motoring groups pointed to research showing that excessive speed was number seven in the cause of accidents. Top of the list was inattention, which might involve drivers looking for speed cameras.

Edmund King, director of the RAC Foundation, said: "Using hidden cameras defies logic. If you put a camera at an accident blackspot it should be visible to slow down traffic not to hand out tickets after a crash."

Clarkson yesterday said: "I've long harboured a suspicion that Brunstrom is off his rocker and this confirms it. I call on him to prove that three-quarters of the population support the current use of speed cameras."
 

More than 80 severely congested junctions will be targeted in a pilot project in London, with local authorities keeping the profits from thousands of penalties issued each day. The Automobile Association expressed concern that authorities would be overzealous in their enforcement to raise extra revenue.

The scheme is expected to be introduced across the country from next year. Transport for London refuses to publish the locations of the first 82 enforcement sites, arguing that revealing the sites would result in motorists obeying rules only at those places, instead of believing there is a chance of being caught on camera anywhere.

The offences to be enforced include disobeying no-entry and "no left turn" or "no right turn" signs, driving in pedestrian zones and blocking "keep clear" areas marked in yellow outside schools. The pilot covers main routes operated by TfL as well as roads controlled by the boroughs of Camden, Ealing, Newham, Croydon, Hammersmith & Fulham and Wandsworth.

Ealing has chosen to pay special attention to schools which have complained that vehicles block school gates, creating a hazard for children. Wandsworth and Newham have identified no-entry signs being routinely abused by drivers and Croydon plans to target drivers who block its tram lines.

But most fines are expected to be generated at junctions covered by yellow boxes which drivers are not supposed to enter unless their exit route is clear. Drivers may enter the box and wait when they want to turn right, and are only stopped from doing so by oncoming traffic, or by other vehicles waiting to turn right.

Nick Lester, director of transport at the Association of London Government, admitted that drivers often became trapped in yellow boxes after following another vehicle.
"There is a certain amount of discretion and you won't be prosecuted if your bumper is over the line. But motorists have to make sensible judgments. If the car in front is zipping through then you could safely follow it. But if it's crawling, then you should wait."

He said poor enforcement of traffic rules was the key problem at a quarter of all London's most congested junctions: "The police, who are currently meant to enforce this, say it isn't a priority for them. By taking over the enforcement we will be able to reduce the delays caused when drivers break the rules to gain one or two minutes' advantage."

Mr Lester said the nine-month pilot would show whether road signs were inadequate or out of date. A high level of fines at a site might indicate the need for better signs. He refused to give estimates for how many fines would be issued but said any profits would be spent on transport improvements. Revenue from traffic offences will be added to the growing pot of money which TfL and councils collect from drivers in bus lanes, the congestion charge and parking fines. Mr Lester said parking enforcement had generated £100 million in profits for London boroughs last year. "If it wasn't for the surpluses the boroughs would find it very difficult to pay for the freedom pass which gives free travel to the over-60s," he said.

Paul Watters, the AA's head of roads policy, said: "We are concerned that CCTV cameras don't give you a chance to explain yourself. The images won't show that you strayed into a junction only because some idiot behind you was blowing his horn." Mr Watters called on authorities to add signs at each junction to make the rules clear. TfL said every junction involved would display a sign saying "Traffic Enforcement Cameras".

The first £100 penalties, which are reduced to £50 for prompt payment, will be incurred on Monday July 5.