A new law designed to protect children from the health dangers of adults smoking in cars has descended into farce after it emerged police are struggling to prosecute offenders.

Police in England and Wales have been “unable” to enforce the ban on smoking in cars carrying children because there are no tickers they can issue, a BBC investigation has found.

Drivers and passengers who smoke in vehicles with children on board should face a £50, under what was described as a “landmark” piece of legislation by the government’s chief medical officer, Professor Dame Sally Davies, when it was introduced.

However the BBC found that no fines or court summons were issued in the three months after the law was passed last October.

The Chartered Institute for Environmental Health, which worked with the government on the law, blamed a bureaucratic mix up after it emerged that authority enforcement officers, the officials who can enforce fines, do not have the power to stop vehicles. Police do have the power to stop vehicles but lack the proper paperwork to issue fines.