Six Nations 2013: England include Billy Twelvetrees and Calum Clark Dates: Saturday 2 February-Saturday 16 March Coverage: Watch live on BBC One, BBC One HD, Red Button and online; listen on BBC Radio 5 live and Radio Ulster MW; text commentary on BBC Sport website and mobiles; watch again on BBC iPlayer Uncapped pair Billy Twelvetrees and Calum Clark have been named in a 33-man England squad for the Six Nations. Gloucester centre Twelvetrees has forged an effective club partnership with Freddie Burns, who is one of three fly-halves in the squad. Northampton flanker Clark served a 32-week ban last season for breaking the arm of Leicester hooker Rob Hawkins. Burns, lock Joe Launchbury, hooker Tom Youngs and prop Mako Vunipola are formally promoted to the senior squad. England kick off their Six Nations campaign against Scotland at Twickenham on 2 February. The requirement for an eight-man replacements' bench means senior squads have been extended to 33 players, with Vunipola the additional prop. Calum Clark fact-file Born: 10 June 1989 2003: Joins Leeds academy at the age of 14 2007: Becomes youngest forward to appear in the Premiership, for Leeds against Saracens 2008: Wins a call-up to the England Under-20s; sent off in the final of Junior World Championship against New Zealand 2010: Signs for Northampton and captains the team, aged 21, in an LV Cup match against Saracens 2011: Named Saints' young player of the season after making more appearances than any other Northampton player, including a start in the Heineken Cup final 2012: Named in Stuart Lancaster's first senior England squad; banned for 32 weeks in March Saracens wing David Strettle has been recalled, with Gloucester's Charlie Sharples dropping out, while Leicester flanker Tom Croft, who only recently returned after neck surgery, is also included. Wasps back-row James Haskell is preferred to Phil Dowson of Northampton, who drops into the second-string Saxons squad. On Tuesday, Leicester fly-half Toby Flood was cleared to play in the Six Nations after a citing for an alleged tip tackle was dismissed at a Rugby Football Union disciplinary hearing. He was cited for a dangerous tackle on Worcester counterpart Andy Goode in the Tigers' 19-14 Premiership win. Stuart Lancaster has been a long-time admirer of Clark, who emerged through the Leeds academy when England's head coach was in charge at Headingley. But Clark's career was put on hold in March, when he pleaded guilty to breaking the elbow of Hawkins in the LV Cup final. Clark's ban ran from 22 March to 1 November, ruling him out of England's summer tour plans and the autumn internationals. Clark, 23, has played the majority of his rugby in the back row but is nominally in the England squad as a second row. With Wasps lock Launchbury, 21, also in, Mouritz Botha and Tom Palmer drop out. Twelvetrees, 24, replaces Leicester's Anthony Allen, Burns takes over from Harlequins' Jordan Turner-Hall, and Leicester's Youngs replaces injured Bath hooker Rob Webber. Burns, Launchbury, Youngs and Vunipola were officially acting as injury cover when they helped England to a record 38-21 victory over the All Blacks in December. Vunipola's younger brother Billy, the Wasps number eight, will train with England in their pre-Six Nations camp in Leeds later this month as cover for Croft. Wasps wing Christian Wade and Bath's former rugby league star Kyle Eastmond are in the Saxons squad, which also includes another league convert in Saracens centre Joel Tomkins. The Saxons play the Irish Wolfhounds on 25 January and Scotland A in Newcastle on 1 February. England senior elite player squad: Forwards: C Clark (Northampton Saints), A Corbisiero (London Irish), D Cole (Leicester Tigers), T Croft (Leicester Tigers), D Hartley (Northampton Saints), J Haskell (London Wasps), T Johnson (Exeter Chiefs), J Launchbury (London Wasps), C Lawes (Northampton Saints), J Marler (Harlequins), B Morgan (Gloucester Rugby), G Parling (Leicester Tigers), C Robshaw (Harlequins), M Vunipola (Saracens), T Waldrom (Leicester Tigers), D Wilson (Bath Rugby), T Wood (Northampton Saints), T Youngs (Leicester Tigers). Backs: C Ashton (Saracens), B Barritt (Saracens), M Brown (Harlequins), F Burns (Gloucester Rugby), D Care (Harlequins), L Dickson (Northampton Saints), O Farrell (Saracens), T Flood (Leicester Tigers), B Foden (Northampton Saints), A Goode (Saracens), J Joseph (London Irish), D Strettle (Saracens), M Tuilagi (Leicester Tigers), B Twelvetrees (Gloucester Rugby), B Youngs (Leicester Tigers). England Saxons elite player squad: Forwards: M Botha (Saracens), N Catt (Bath Rugby), L Deacon (Leicester Tigers), P Doran Jones (Northampton Saints), P Dowson (Northampton Saints), W Fraser (Saracens), J Gray (Harlequins), G Kitchener (Leicester Tigers), S Knight (Gloucester Rugby), M Kvesic (Worcester Warriors), M Mullan (Worcester Warriors), D Paice (London Irish), T Palmer (London Wasps), G Robson (Harlequins), E Slater (Leicester Tigers), H Thomas (Sale Sharks), B Vunipola (London Wasps). Backs: N Abendanon (Bath Rugby), A Allen (Leicester Tigers), T Biggs (Bath Rugby), E Daly (London Wasps), K Eastmond (Bath Rugby), G Ford (Leicester Tigers), G Lowe (Harlequins), J May (Gloucester Rugby), U Monye (Harlequins), J Simpson (London Wasps), C Sharples (Gloucester Rugby), J Tomkins (Saracens), J Turner-Hall (Harlequins), C Wade (London Wasps), R Wigglesworth (Saracens).