Television:
* The Crown (2016-2020) as Group Captain Peter Townsend
* The Last Kingdom (2015-2022) as Aethelred
* The Musketeers (2014-2016) as Monsieur d'Artagnan
* The White Queen (2013) as Edward IV
* Ripper Street (2012-2016) as Constable Drake
* Call the Midwife (2012-2014) as PC Noakes
* Lewis (2010-2015) as DS James Hathaway
* Robin Hood (2006-2009) as Allan-a-Dale
Film:
* The Last Kingdom: Seven Kings Must Die (2023) as Aethelred
* The King's Speech (2010) as David, the King's Footman
* The Duchess (2008) as Lord Frederick
* St Trinian's (2007) as The Doctor
* The History Boys (2006) as Posner
Other:
* The Last Kingdom: Seven Kings Must Die (2023) - TV Movie (as Aethelred)
This is not an exhaustive list, but it includes his most notable projects. You can find a more complete filmography on websites like IMDb.