Revealed in a review of the club's first-quarter accounts on Wednesday, United earned a total of £17.3m from the sale of Adnan Januzaj and two sell-ons in the previous transfer window.

Those sell-ons, and the £9.3m of profit, are understood to have come from Keane's £30m move from Burnley to Everton and Drinkwater's £35m transfer from Leicester to champions Chelsea.

Danny Drinkwater never made a first-team appearance for United

The rest was the £8m transfer fee from Belgian Januzaj's transfer to Real Sociedad in Spain.

Stockport-born centre-back Keane joined United as an academy scholar in 2009 at the age of 16. He signed his first professional contract with the club on his 18th birthday on January 11, 2011, before making his first-team debut later that year.

Keane would go on to make only four further appearances for United before a loan move to Burnley was made permanent in the summer of 2015.

Manchester-born Drinkwater joined the academy at the age of nine in 1999 and became a trainee in 2006. He never made a first-team appearance for United and spent time on loan at Huddersfield, Cardiff, Watford and Barnsley before signing for Leicester in 2011.

He and Keane played together at the Foxes while the defender was on loan from United during the 2012-13 season.