One in three people diagnosed with asthma may not have it, NHS watchdogs have warned, as they urge GPs to carry out “objective tests” on patients,

New guidance from National Institute for Health and Care Excellence (Nice) tells doctors to run spirometry and breath tests, to improve accuracy of diagnosis and treatment.

The new guidance says better testing could avoid patients being needlessly prescribed medication, and save the NHS up to £15m a year.

Around 4.5 million people in England currently receive treatment for the inflammatory lung disease which causes wheezing, breathing problems and chest tightness.