Ifill's fee could rise to �1m

Ifill, 25, has signed a three-year deal with the Bramall Lane club and the fee could rise to �1m depending on appearances and the Blades' progress.

"He's a player I've wanted to sign for years," United boss Neil Warnock said.

"He is the type of player we want - strong, quick, at a great age and I believe he could walk into a Premiership side already."

Ifill becomes the Blades' second signing of the week, following the arrival of Leicester City midfielder Lilian Nalis.

Warnock added: "I think with Paul, Lilian and two or three others I want to bring in, supporters can see we are trying to bring in the quality needed to supplement what is already a very good squad.

"It's great for Sheffield United fans to see the club bringing in this type of quality because it shows just which direction the directors and I want the club to go in."

Ifill has struggled with an ankle injury in recent months but recovered to play in the final few games of last season.