HEATHER MILLS Home Affairs Correspondent A senior police officer broke ranks yesterday and joined the judiciary's

HEATHER MILLS Home Affairs Correspondent A senior police officer broke ranks yesterday and joined the judiciary's attack on the Home Secretary's plans to incarcerate thousands more men and women under sweeping sentencing reforms.The Chief Constable of Humberside, Tony Leonard's surprise criticisms of Michael Howard's sweeping sentencing reforms, came as the new head of the Prison Service said that 25 new jails would be needed over the next 10 years - at an estimated cost of more than pounds 6bn - to cope with the explosion in the prison population.Mr Leonard forced Mr Howard on to the defensive, when the Home Secretary was on a visit to Grimsby. I'd rather see that money ploughed into policing and preventing crime."And he added: "I agree with the Lord Chief Justice in that I don't think Parliament should set minimum sentences. The law should set maximum sentences and should trust the judiciary to implement sensible arrangements as to the length of the sentence."It was a major embarrassment for Mr Howard. Mr Leonard - who was showing off his force's new high-speed pursuit car - called into question the whole basis of Mr Howard's sweeping sentencing reforms, outlined in Wednesday's White Paper.Mr Leonard said the hundreds of millions of pounds the Government was planning to pour into a major prison-building programme would be better spent on crime prevention and questioned the minimum sentences for violent and sex offenders, and repeat burglars and drug dealers.He said: "It's going to cost an awful lot of money in terms of building new prisons. In all, 2 million passengers will pass through the airport by 13 April.Transport failure, page 4. "It looks like the weather is going to be great, so the coast and many Easter events could well attract record crowds."Forecasters predict it will remain sunny until tomorrow when it will become cloudier, although it should stay dry.

About 1.5 million Britons will spend the holiday abroad, with Heathrow yesterday handling 165,000 passengers. We're looking at some pretty bad delays." Routes out of London and in the West Midlands were particularly busy, as were all roads leading to airports and ports.And an AA spokesman warned drivers to plan journeys to avoid bottlenecks. This means that five minutes after the event occurred, people a mile away are still slowing down.When the traffic is heavy, that quickly leads to "flow breakdown", wherever the number of cars on the road is at a critical level - around a hundred cars passing any point every minute The result: a traffic jam appears from nowhere. Bad lane discipline, such as middle lane hogging, makes it more likely, by reducing the road's capacity."On the M25, we found that in the four-lane section, when all are properly used, you can get 8,000 vehicles past a point in an hour," said Dr Smith. "When you get everyone bunched into the outside lane, because there's an empty inside lane, a lorry in the second lane, and a car travelling at the same speed as the lorry in the third lane, the flow falls to 2,500 vehicles."Their work, in a project called Paramics, at the university's Parallel Computing Centre, may lead to "traffic forecasts" that enable drivers to find out which roads will be busy, based on the traffic which is already on them.Those setting off for Easter breaks may have been grateful for forecasts yesterday as big jams built up, with routes out of many big cities described as "a nightmare".Motorists have been warned to expect long delays over the weekend as holidaymakers are joined on the roads by people tempted out by good weather.A spokesman for the RAC said yesterday: "There are certain points around the country where it really is horrendous. He said an aeroplane passing overhead, or an accident on the other side of the road, can lead to a "shockwave" of braking, which travels back through the traffic queue, as drivers react to brake lights in front by braking themselves at up to 12 miles per hour.

The last two, both of which were fatal, occurred in New Jersey in December 1994, and in California in April 1995.. CHARLES ARTHUR Science Correspondent and ROB CRANEFor drivers across Britain this Easter, it will be a familiar scenario: sit in a jam for hours, only to find, when the traffic begins to move again, that there was no apparent reason for it.Now, a super-computer produced by a team of scientists in Edinburgh has shown what causes inexplicable hold-ups: drivers who sit in the middle lane, and those who follow too closely behind the car in front, and have to brake abruptly."You'd be surprised at what people slow down for," said Mark Smith, marketing director for Quadstone, a spin-off company formed by the Edinburgh team. Just as the FBI's psychological portrait of their quarry suggested, he is a white male, well-educated, meticulous and deeply antisocial.Mr Kaczynski lived as a recluse in remote Montana for at least a decade, hardly known by his neighbours, who considered him a quiet and harmless eccentric. The Unabomber's attacks have taken place all over the country. The decisive break in the case seems to have come from tips from family members, especially David Kaczynski, who noticed similarities between some of his brother Theodore's earlier writings and published material from the Unabomber.The manhunt which may now have climaxed has been the longest and most expensive in the FBI's history, led by a permanent 40-man task-force based in San Francisco.

Over the years of the investigation, 200 people were briefly detained before being released.But Mr Kaczynski is by far the strongest suspect so far unearthed. Apart from the physical evidence reportedly discovered at his cabin, he fits the identikit profileperfectly. The examination of the cabin where Kaczynski lived a hermit's existence without electricity or running water could take several days - not least because of fears of booby traps. The device was apparently discovered by investigators as they searched Mr Kaczynski's remote cabin near the small town of Lincoln on Wednesday afternoon.The charge means that Mr Kaczynski, detained when he tried to prevent the search, can continue to be held in custody while further evidence is amassed at the cabin - evidence the FBI hopes will conclusively identify him as the Unabomber, responsible for killing three people and wounding 23 others in 16 separate attacks, the first of them in May, 1978.Although long years of failure have taught the authorities to be cautious, they finally believe they have caught their man.