Derby have completed the signing of Manchester United midfielder David Jones in £1million-plus deal.
The 22-year-old, who had been on loan at Pride Park since November, has agreed a three-and-a-half-year deal with the Championship promotion contenders.
Jones made four appearances for the Red Devils and has played for England Under-21s.
'I'm delighted to have secured the services of such a talented young player,' said Derby manager Billy Davies.
'I'm sure from what he's shown for the Rams so far that the Derby fans will know we've signed a first-class footballer.
'David has settled in really well at the club and shown signs of his quality.
'I'm sure he will get better and better the more games he plays.
'As I've said so many times, we've got a long-term plan at this football club, so with his age, potential and ability, I see no reason why a player like David can't be a major influence in a Derby shirt.'
Meanwhile, midfielder Paul Thirlwell has left the club to join Carlisle for an undisclosed fee.
The 27-year-old has signed a permanent deal with the League One side having spent three months on loan with them earlier this season.