Sharapova reveals she failed drug test at Australian Open

Former world number one Maria Sharapova has revealed she failed a drugs test at the Australian Open.

The Russian, 28, tested positive for meldonium, a substance she has been taking since 2006 for health issues.

The International Tennis Federation (ITF) said the five-time Grand Slam champion would be provisionally suspended from 12 March. Sportswear company Nike said it was halting its relationship with her until the investigation was complete.

"I did fail the test and take full responsibility for it," said Sharapova, who won Wimbledon as a 17-year-old in 2004.

Sharapova has been the highest-earning female athlete in the world in each of the past 11 years, according to the Forbes list.

With career earnings from tennis alone amounting to almost £26m, she claimed she had taken meldonium "for the past 10 years" after being given it by "my family doctor" but had known the drug as mildronate.

Meldonium is meant for angina patients but athletes use it because it helps their endurance and ability to recover from strenuous activity.

Sharapova started to take meldonium after her doctor did "an extensive battery of tests to determine what medical conditions were causing her to be sick on a frequent basis".

She had "abnormal electrocardiogram readings" and "some diabetes indicators", which prompted the doctor to recommend medication, including meldonium.