Leeds had earlier dismissed claims that a deal had already been agreed to sell the striker to their rivals.

But the transfer, which could see Danny Pugh head the other way, is expected to be announced to the Stock Exchange once Smith has completed a medical.

Leeds rejected bids of 3.5 million pounds and 5.5 million pounds from United last week and were waiting for United to match their valuation.

Everton had made a seven-million-pound bid for Smith, while Newcastle and Middlesbrough were also thought to be interested.

But Smith is thought to want a move to United, with the prospect of Champions League football to look forward to.

Sir Alex Ferguson already has Ruud van Nistelrooy and Louis Saha as first-choice strikers with the likes of Ole Gunnar Solskjaer and David Bellion capable of operating up front.

Smith would give United's manager more options in that department, with the bonus that he can also play in midfield.

However, his arrival in Manchester might also cast a shadow over Van Nistelrooy's future, with Real Madrid constantly linked with a 40-million-pound move for the Dutchman.