The world's biggest drugs firms could abandon Britain and delay launching medicines unless an extra £20 billion is pumped into the NHS, according to a leading pharmaceutical association.

The Association of the British Pharmaceutical Industry (ABPI) is demanding an increase in health spending from 9.9 per cent to 11 per cent of GDP in "detailed" election campaign requests, which has prompted criticism of "special pleading" from Tory MPs.

Lisa Anson, the new president of the ABPI, suggested that a funding squeeze on the health service could lead to an exodus of drugs firms from Britain, The Times reports.

Ms Anson, who is also the head of drugs firm AstraZeneca, also said the future of the £30 billion life sciences sector could be in jeopardy.