The 18-year-old was signed up by the Blades' academy in 2002, and has made one appearance this season.

Blades boss Neil Warnock told United's website: "I'm absolutely delighted. I have every confidence in him becoming an established player for us.

"He has an eye for goal. This will give other academy lads extra incentive."

Law said: "I'm obviously pleased because my contract was up at the end of the season, so to be offered another one shows United want to keep me.

"I'm enjoying it here, everything is going well at the moment, and I hope to progress and make a proper breakthrough."