Dr Brennan, who was the clinical director of the service from October 1990 until he took paid leave in June 1997, failed to carry out a key test on dozens of women which involves taking a sample of cells from the suspected cancer with a fine needle, the GMC was told.

BBC: Doctors 'failed breast cancer patients'

Instead of taking the temperature of a representative sample of customers, firms must identify the few special customers who innovate.

ECONOMIST: The future of innovation

Taking a sample from one part of a tumour may not reveal its full genetic identity, according to research by scientists from Cancer Research UK (CRUK).

BBC: DNA analysis shows huge genetic diversity in tumours

In truth, though, this is hardly a representative sample, since the exhibitionists taking part are goaded on by the presence of the cameras.

ECONOMIST: We love you, Big Brother