New England Patriots quarterback Tom Brady has dropped his appeal against a four-match suspension, he announced on Friday.

The Patriots were found to have used under-inflated footballs in their AFC Championship game against the Indianapolis Colts in January 2015.

Brady managed to get his suspension overturned to begin the following season, but, as a complex legal process dragged on, it was re-imposed for the start of the 2016 season.

Having been denied a rehearing by the Second Circuit appeal court, Brady has finally admitted defeat.

In a statement on his Facebook page, Brady wrote: “I’m very grateful for the overwhelming support I’ve received from (team owner Robert) Mr Kraft, the Kraft family, coach (Bill) Belichick, my coaches and team-mates, the (NFL Players’ Association), my agents, my loving family and most of all, our fans.

“It has been a challenging 18 months and I have made the difficult decision to no longer proceed with the legal process.

“I’m going to work hard to be the best player I can be for the New England Patriots and I look forward to having the opportunity to return to the field this fall.”

He will be unable to do so until the October 9th clash with the Cleveland Browns, with back-up Jimmy Garoppolo in line to start the four games prior to that.

Brady was banned after an investigation by attorney Ted Wells ruled it was "more probable than not" that he was "at least generally aware" of wrongdoing by team staff.

An initial appeal to league commissioner Roger Goodell failed, but the suspension was nullified in September 2015 by Judge Richard M Berman.

The US Court of Appeals reversed Judge Berman’s decision in April 2016 and Brady failed with a further appeal to the Second Circuit.

With the Supreme Court his only remaining avenue, he will take the matter no further.