To the man with a hammer, every problem looks like a nail. For years, computer firms have been lobbying the government with the message that the way to save the UK's creaky criminal justice system is to buy more IT.

Their wish is about to be granted. A forthcoming white paper on criminal justice will propose creating new electronic networks to join up police forces, courts, prison and probationary services.

At a recent conference sponsored by Schlumberger-Sema, the IT services firm, Tony Blair promised "a major investment in IT" to replace systems "still in the dark ages".

The Audit Commission reported last month that every year, the system wastes £80m when trials are adjourned, delayed or collapse unnecessarily, usually because of failures in communication between different agencies.

The commission says that information sharing "is severely hampered by out of date and non-integrated information technology".

It also points to cultural barriers to adopting modern IT by lawyers and other professionals. While some use email and electronic case- files, "others appear unconvinced about the reliability and accessibility of electronic communication". Even where systems are integrated, case papers are still faxed.

If police officers, probation workers and lawyers are "unconvinced" about IT, they have some excuse. The 1990s were littered with fiascos.

* Fingerprint recognition. The first attempt to set up a national fingerprint recognition system, due to be in place by 1995, collapsed. Its replacement reached all police forces only last year.

* Probation case-management. In the 1990s, the National Probation Service's Information Systems Strategy had seven project managers in seven years and was never completely rolled out. By last year, its cost had risen to £118m, 70% above the original forecast.

* Police National Computer. The Audit Commission found widespread dissatisfaction with the system, which relies on updating by messenger or fax, as well as computer.

* Libra, a system developed for the lord chancellor's department to automate magistrates courts, is running behind schedule, ministers admitted this year. The cost of the contract has increased from £183m to £319m.

One of the speakers at last month's conference, David Tait, SchlumbergerSema's managing director, public sector, says there are two reasons for cautious optimism.

First is the XML mark-up language, which allows previously incompatible systems to share information via a web-browser. "Ten years ago, we'd have had to throw all the existing systems away and design one mega system," he said. Second, Tait says that breakthroughs in security technology should remove some of the worries about linking information systems.

Today, the criminal justice "system" consists of seven main agencies, overseen by three departments - the home office, the lord chancellor's department and the attorney general's office.

Senior police officers are calling for a continental-style ministry of justice to run the whole system. The white paper will not go that far, instead proposing the creation of local criminal justice "communities" working together. IT will provide the glue, joining up systems and providing management that will identify bottlenecks.

Tait warns that such links may not happen unless agencies are compelled to put them in place. He is probably pushing at an open door. In November, the home office appointed a new director general for criminal justice IT. Jo Wright, previously a director at IBM, is drawing up an IT strategy that is likely to be more in tune with what industry believes is possible rather than with maintaining professional and organisational traditions.

One idea from Tait is a national court-scheduling service. This would connect courts, police forces, the prison services and witness support agencies to synchronise court hearings. It would probably be run by an IT services contractor under a public-private partnership.

How much will it all cost? Tait says that, for all the technical and organisational challenges, the investment will not be huge compared with that needed for a similar scheme in the NHS. "I would be surprised if it reached a billion pounds."

However, earlier this month, Lord Justice Brooke, chairman of the judges' standing committee on IT, said that modernising courts' computers might need an investment of £500m.

Recession-hit IT companies are drooling at the prospect.

· Route to Justice. Audit Commission www.audit-commission.gov.uk