[2] He was dual registered with National League 1 side Ealing Trailfinders for the 2011–12 season and made his first appearance in senior rugby on 7 January 2012 against Jersey.

[3] He joined Esher on a similar agreement the following season and also made his senior debut for Harlequins in November 2012 as a replacement in the 31–30 Anglo-Welsh Cup win over Northampton Saints.

[6] Born in Brisbane, Australia to a Kenyan father and an English mother, Clifford has captained England under-18 and under-20 level.

[9] Clifford received his first call up to the senior England squad by new coach Eddie Jones on 13 January 2016 for the 2016 Six Nations Championship.

[10] He made his full debut as a replacement for Chris Robshaw during the Calcutta Cup match against Scotland on 6 February 2016 after 69 minutes.