Every cancer patient in Britain should undergo DNA gene sequencing to prevent the misery of misdiagnosis, needless hospital visits and ineffective chemotherapy, the Chief Medical Officer has said.

In her annual report, Dame Sally Davies, said it was time to end the ‘diagnostic odyssey’ which left the average patient with a rare disease forced to consult five different doctors and wait four years before a correct diagnosis.

Dame Sally said the NHS must embrace DNA testing which, from a small sample of blood or saliva, can correctly identify not just illnesses but also specific genetic mutations which play a dramatic role in success of treatments.