Rory McIlroy's Commercial Court battle with his former agents Horizon Sports Management is due to start today.

The golfer claims he was young and inexperienced and signed an unconscionable contract with Horizon at a Christmas party in 2011 without the benefit of independent legal advice.

In a counterclaim Horizon alleges it's owed a cut of the golfer's earnings. It also alleged Rory McIlroy had wiped data from his phones.

The court battle is expected to run for two months.