By Nick Triggle
Health reporter, BBC News
Extra security on doors may be one solution, experts say
The NHS has launched an investigation into thefts, amid reports criminals see the service as an "easy target".
Among the items snatched have been ambulance satellite navigation systems, patients' belongings and hospital equipment and laptops.
The NHS Security Management Service believes the health service is vulnerable because large parts of its estate have to be open to the public.
It wants to see if extra measures need to be put in place to improve security.
Figures show there have been 57 "high-value claims" - those worth more than £20,000 - over the past five years.
Mobile scanner unit targeted by thieves in Northamptonshire, causing delays for scores of patients
Computers stolen from London's St George's Hospital, containing the details of 20,000 patients
Laughing gas snatched from Devon's Torbay Hospital
Money and photographs stolen from elderly woman as she lay in bed in Worcestershire Royal Hospital
Medical equipment, including a £6,000 heart machine, taken from ambulances in Mansfield and Bournemouth
Hospitals across the country targeted for endoscopic equipment several years ago. Police believe it was sold abroad
But it is thought this is just the tip of the iceberg, as reports are regularly emerging of more and more thefts.
Earlier this month, equipment was stolen from a mobile scanner unit in Corby, Northamptonshire, delaying the appointments of scores of patients.
And in recent months, there have been several reports of ambulances being raided for medical equipment, while London's St George's Hospital had laptops containing data from 20,000 patients snatched last year.
One of the problems is that the public is free to come and go in many NHS sites and this leaves them vulnerable, the experts say.
In fact, some large hospitals can see as many as 8,000 visitors a day.
And now security chiefs have asked every trust in England to give them details of thefts to see what can be learned.
Jill Abethell, who is overseeing the investigation for the security service, said: "We have decided to look at theft as we believe it is a real problem.
"I think like any organisation open to the public there is that risk something can be stolen.
"We have heard of ambulances having sat-navs and equipment stolen out the back while crews treat people on the street and laptops going from hospitals.
"We want to find out more so we can look to see if measures can be taken to protect property."
She accepted there was a limit to how much could be done to make public places, such as hospitals, more secure but said security codes on doors or more surveillance might help.
Jonathan Fox, of the Association of Professional Ambulance Personnel, said: "Most people will find it astonishing that people can take things like this.
"But I am afraid it does happen. In many ways the NHS is an easy target. But in the case of ambulances, every time there is a theft that vehicle has to be taken off the road and that means patients are put at risk."