BBC News Online explains why the bill is so high and what is being done to reduce the costs.

What is clinical negligence?

Clinical negligence is the term given to a breach of duty of care by health care practitioners, including doctors and nurses.

It can cover mistakes or errors that occur in everything from prescribing and administering drugs to carrying out complex surgery.

Why are costs increasing?

The total clinical negligence bill has increased from �2.3bn in 1998 to �4.4bn in 2001.

The rise is attributed to an increase in the number of cases being taken by patients rather than an increase in mistakes by medical staff.

Experts suggest it is now easier for members of the public to take lawsuits and to sue for compensation. Patients are also much more aware of their rights and are more likely to seek legal redress when things go wrong.

Meanwhile, the courts have also increased the amount of money it awards to patients who win clinical negligence cases.

What is the impact on the NHS?

The impact of these clinical negligence claims on the NHS is significant.

The total bill in 2001 is estimated to be �4.4bn. That sum will be paid out over around 10 years.

The overall health service budget in 2001 was �54bn.

Individual trusts are responsible for meeting the costs of any clinical negligence claims made against it or its staff.

As a result if the bill is particularly high, then trusts may have to reduce services to ensure its financial accounts balance at the end of the year.

With NHS funding set to increase substantially in the coming years, there are fears that the clinical negligence bill will keep pace and seriously dent the impact of the billions of extra pounds promised in April's Budget.

What is being done to tackle the problem?

The government has long acknowledged that something needs to be done to tackle the rising cost of clinical negligence claims. However, it has been slow to introduce changes.

In April 2000, the government established the NHS Litigation Authority to take over responsibility for all negligence cases. This had previously been done by individual trusts.

The organisation is responsible for ensuring all cases are treated consistently and for paying out to patients with the money coming out of the accounts of trusts.

The chief medical officer for England Prof Sir Liam Donaldson is carrying out a review of clinical negligence procedures and is expected to publish a White Paper outlining proposed changes within months.

He is believed to be considering introducing a 'no-fault' compensation or fixed fees scheme as part of efforts to keep a cap on the rising costs.

Will the costs fall in the years ahead?

No - the likelihood is that the NHS negligence bill will continue to rise.

However, Sir Liam's proposals may help to stem the size of the annual increases.

A new scheme to restrict the amount of money being paid to patients when things go wrong will if introduced help to rein in the rising costs of paying for medical mistakes and errors.