Casper joined the club initially on loan during the latter half of the 2006/07 season before signing a three-year contract with the club at the beginning of August 2007, after initially coming from Brondby on a loan deal at the start of the year.

He was the first player to sign a contract after the club emerged from administration.

The 6ft 3in keeper establikshed himself as a regular during the 2007/08 season, making 50 appearances, and he went on to make 39 first team appearances the following season.

After starting the season as No 1 keeper injury kept him out of a number of games, when his place was taken by Dave Lucas, who clocked up 18 appearances.

But once Simon Grayson had taken over as manager, Ankergren became his first choice keeper for the remainder of the season and he played in the final 27 matches of the season, keeping 11 clean sheets as United battled their way to the to the Play-Offs.

Now in his third full season with the club, Casper had clocked up over 100 appearances for Leeds United by the end of the 2008/09 season, reaching his century in a 1-0 win at Hartlepool United on April 25.

However, following the summer 2009 arrival of Shane Higgs, Casper found himself on the bench at the start of the new campaign.