LONDON (AFP) - Shamed former England international footballer Adam Johnson will serve his six-year sentence for sexual activity with a 15-year-old girl after a judge refused him leave to appeal against his conviction.

The 28-year-old, once a winger with Sunderland and Manchester City, was jailed in March after beng found guilty following the illegal act which took place in his Range Rover last year.

Johnson, capped 12 times, also pleaded guilty to another count of sexual activity with a child and one count of grooming a child.

His sister Faye, who had started up a Facebook page called 'Adam Johnson's Appeal Fight', tweeted she was devastated by the judge's decision.

A statement from Johnson's solicitor said: "We have received notification that Adam Johnson's applications for leave to appeal against his conviction and sentence have been refused by the Single Judge.

"He is obviously disappointed - having carefully considered all of the information, we will be lodging renewed applications on conviction and sentence in the coming days."

Johnson was sacked by Sunderland in February as the club terminated his £60,000-per-week (S$106,250) contract.