Yesterday he highlighted the difficulty in diagnosis by showing a scan in which his metal implant had caused an area of indecipherable blackness around his right hip.

Eight months after her veneers had been fitted, one tooth came away completely with the veneer, so she had to have a metal implant and crown to replace the tooth.

The technique involves resurfacing an existing hip joint with toughened ceramic instead of the traditional full metal implant.

She then retraces her steps and finds that most of the people she ran into before now have some sort of metal implant.

The process takes five to 10 days from the date of the scan to surgery, compared with six to eight weeks with the typical metal implants.