England coach Stuart Lancaster has made seven changes to his elite player squad for the Six Nations Championship, with debutant Calum Clark and winger Billy Twelvetrees both included.
Joe Launchbury, Tom Youngs and Mako Vunipola are all officially promoted from the Saxons squad while Freddie Burns, James Haskell, David Strettle are also included following appearances in the Autumn series.
Billy Vunipola, who will train with the senior squad in their pre-Six Nations training camp in Leeds, is among seven changes to the Saxons squad, which also includes Tom Palmer, Rob Webber, Charlie Sharples, Anthony Allen, Mouritz Botha, Phil Dowson and Jordan Turner-Hall, all of whom are demoted.
"The fact that we have spent significant time deliberating over quite a few players shows how tough the competition is to get into this 65 and the strength in depth that is emerging. We have made some changes to both squads and we feel that reflects the players' form during the first half of the season," Lancaster said.
"There will be undoubtedly be movement between the two squads as we go through the RBS 6 Nations and that was evident in the QBE Internationals, with players in form pushing through such as Freddie Burns, Joe Launchbury, Tom Youngs and Mako Vunipola.
"This is a very important year for England, with the Six Nations and the Saxons games to look forward to so there are some great opportunities for the players to demonstrate their club form at international level.
"The summer tour to Argentina will also be a great chance for those players pushing for a place, especially with some of our senior squad hopefully going with the Lions, and chances will undoubtedly arise as we hope to play two midweek games as well as the two Tests."
Tom Croft will continue his return from eight months out with broken neck by training with the senior squad but is unlikely to feature in the Six Nations.
Toby Flood, one of three fly halfs in the 33-man squad, is available after being cleared by the Rugby Football Union for an alleged tip tackle on Worcester's Andy Goode.
Five of the players who featured in the mesmeric victory over New Zealand in December, Launchbury, Youngs, Vunipola, Haskell and Burns, are the big winners from Lancaster's latest squad, his second as permanent England coach.
England start their Six Nations campaign on 2 February against Scotland.
England Senior Elite Player Squad:
Forwards: D Cole, J Marler, A Corbisiero, M Vunipola, D Wilson, D Hartley, T Youngs, G Parling, C Lawes, J Launchbury, C Clark, T Wood, C Robshaw, B Morgan, T Croft, T Johnson, J Haskell, T Waldrom,
Backs: B Youngs, D Care, L Dickson, O Farrell, T Flood, F Burns, M Tuilagi, B Barritt, J Joseph, B Twelvetrees, C Ashton, D Strettle, B Foden, M Brown, A Goode
England Saxons Elite Player Squad:
Forwards: M Botha, N Catt, L Deacon, P Doran Jones, P Dowson, W Fraser, J Gray, G Kitchener, S Knight, M Kvesic, M Mullan, D Paice, T Palmer, G Robson, E Slater, H Thomas, B Vunipola.
Backs: N Abendanon, A Allen, T Biggs, E Daly, K Eastmond, G Ford, G Lowe, J May, U Monye, J Simpson, C Sharples, J Tomkins, J Turner-Hall, C Wade, R Wigglesworth.