A British minister has ordered an urgent investigation following claims an Irish-born doctor was secretly filmed telling how he prescribed performance-enhancing drugs to sports stars.

It follows a report in The Sunday Times that an Irish doctor was secretly filmed telling how he prescribed performance-enhancing drugs to sports stars.

The doctor, named by the newspaper as Dr Mark Bonar, claimed he treated more than 150 sports people with banned substances including EPO, human growth hormone and steroids, according to an investigation by the newspaper.

He allegedly said he treated footballers at Premier League clubs including Chelsea, Arsenal and Leicester City along with British Tour de France cyclists, tennis players and a British boxer.

Premier League clubs Arsenal, Chelsea and Leicester have strongly denied allegations any of their players have doped.

The three Premier League sides said they were "disappointed" by the claims and stressed their teams followed strict anti-doping protocols.

In a statement, Chelsea said: "The claims The Sunday Times put to us are false and entirely without foundation.

"Chelsea Football Club has never used the services of Dr Bonar and has no knowledge or record of any of our players having been treated by him or using his services.

"We take the issue of performance-enhancing drugs in sport extremely seriously and comply fully with all anti-doping rules and regulations."

The newspaper claims the UK Anti-Doping (UKAD) watchdog was given information about the doctor's alleged doping activities two years ago but failed to take action to stop him.

London-based Dr Bonar denied the allegations when they were put to him by the newspaper and said he had not breached rules laid out by the General Medical Council (GMC), which regulates doctors.

Dr Bonar is facing disciplinary hearings that could see him struck off for a separate allegation of providing a patient with inadequate care, the GMC said.

Culture, Media and Sport Secretary John Whittingdale said: "Sports fans are entitled to be sure that what they are watching is true and fair with all athletes competing on a level playing field.

"I have asked for there to be an urgent independent investigation into what action was taken when these allegations were first received and what more needs to be done to ensure that British sport remains clean.

"There is no room for complacency in the fight against doping and the government is already looking at whether existing legislation in this area goes far enough.

"If it becomes clear that stronger criminal sanctions are needed, then we will not hesitate to act."

Dr Bonar, 38, is alleged to have charged clients thousands of pounds for illicit drug programmes.

UKAD officials confirmed they received information from a sportsman in April and May 2014, but said the doctor fell outside their jurisdiction and they did not believe there were grounds to refer the case to the GMC.

In October 2014 the sportsman, who has not been named, supplied UKAD with "handwritten prescriptions" he said had been issued by Dr Bonar, it is claimed.

The notes were given to an independent medical expert for analysis.