Cancer patients' lives are being put at risk because Britain is lagging behind the rest of Europe and the US in providing vital scans, leading charities have warned.

The scans by the five Positron Emission Tomography (PET) machines are vital to give cancer sufferers a fighting chance of improving their treatment and survival.

But there are only five of the PET scanners in use in the NHS - all of which are in London - with others in research centres or the private sector.

Charities including Macmillan Cancer Relief, the British Lung Foundation and CancerBACUP have joined forces to call on the Government to make sure more PET scanners are available across England and Wales.

It comes only a month after The Northern Echo revealed that a new £1m brain scanner was lying idle because of staff shortages.

Bosses at the James Cook University Hospital, in Middlesbrough, admitted in October that the new magnetic resonance imaging (MRI) scanner which arrived in the summer had yet to be used on a single patient because there was no staff trained to use it.

It adds to the radiotherapy crisis recently reported by The Royal College of Radiologists (RCR) which said that despite Department of Health and National Lottery money to update equipment, patients are still suffering due to staff shortages and a lack of machines.

The RCR report, which looked at equipment, workload and staffing for radiotherapy in the UK between 1997 and 2002, found that despite a 16 per cent increase in demand for treatment, megavoltage machines in clinical use for radiotherapy had only increased by ten per cent.

The hi-tech PET machines are used to either detect disease or to find out how widespread a disease, such as cancer or epilepsy, is in a patient's body.

According to the charities, the machines make a real difference in at least a quarter of all lung cancer cases as well as other diseases, and could put an end to pointless surgery.

They have called for scanners to be put in to at least 15 sites in Britain in the next three to five years.

Former leading surgeon Jules Dussek said: ''I would be very unhappy if I would be forced to operate on someone with lung cancer without a PET scan. I would feel naked and defenceless.''