The use of tissue goes far beyond the familiar world of organ transplants, and involves a host of different materials including bone, skin, muscle, tendons and ligaments.

Bones can be used in fracture repair, skin can aid wound healing, and heart valves can be used as replacements in ailing patients.

Tendons and ligaments may be used to treat sports injuries, long bones to replace those damaged by cancer, shaped-bone products in spinal surgery, and ground bone in dental surgery. Collagen can be used to plump up lips, while bodies or body parts can be used in crash tests or in demonstrations of new techniques for surgeons.

In Britain the number of body parts that are taken in is unknown, because there is no requirement to keep a tally. Premises that store tissues, however, have to have a licence from the Human Tissue Authority (HTA), and of these 41 are either importing or exporting tissues.

The quantity of such imports and exports is not known, because the HTA does not gather figures.

There are moves to change the law so that such data would in future be collected. Up to 77 patients in Britain may have had grafts from bones imported from the New Jersey company involved in the Alistair Cooke case, the Medicines and Healthcare products Regulatory Agency said last month.

Patients were offered screening and counselling to detect any problems.

Every year it is estimated that 25,000 US bodies are used as source material for as many as 750,000 operations and procedures.

Heart valves can fetch up to $7,000 each, and skin $1,000 per square foot. A body could be worth about $150,000 if broken down into its component parts, according to Art Caplan, Professor of Bioethics at the University of Pennsylvania.

There are two legitimate sources of body parts in the US. The vast majority of bodies donated to science go to medical schools, where they are used to teach anatomy.

Surplus parts can be sent to not-for-proft biomedical corporations, and it is illegal to charge for them. But medical schools can charge fees to cover administrative costs, and these can be high.

A second source is the tissue and organ banks, non-profit organisations to whom individuals can leave their bodies. They are often linked to trading companies to whom they pass on the parts.

There is no real ethical reason why the trade should not continue, so long as proper consents are obtained.

But some orthopaedic surgeons, such as Professor Angus Wallace, of Nottingham University, believe that officials are discouraging the harvesting of parts because of fears of an Alder Hey-style public backlash.

He believes that it is unethical to treat British patients with imported body parts and could be dangerous because of uncertainties over quality.

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