Blackwell, who has overseen a dramatic climb to the cusp of the play-offs since taking over from Bryan Robson in February, will be unveiled at a press conference at Bramall Lane on Saturday morning.

Plc chairman Kevin McCabe will make the announcement ahead of the Blades' crucial last match at Southampton on Sunday, when a victory, allied with defeats for Wolves, Ipswich and Crystal Palace, will see United sneak into the top six.

Blackwell was temporary replacement for Robson, who left the club by mutual consent in mid-February, and held talks with McCabe over his future last weekend.

The former Leeds and Luton manager, who was assistant to Neil Warnock at Bramall Lane, has transformed the club's fortunes since his return.

The Blades were staring at a relegation fight following Robson's tenure but have since gone on a run of two league defeats in 13 matches, taking them to within two points of the play-offs.