United have allowed Leigh Bromby to join Watford on the eve of the transfer deadline.

The 27-year-old defender, who has been in and out of the Blades side during the last few seasons, has signed for the Hornets on a three-and-a-half-year deal. United will receive an initial fee of £600,000, which could rise to £850,000 on certain criteria being met.

Bromby joined the Blades from local rivals Sheffield Wednesday on a free in the summer of 2004 and made 125 appearances, the last of which being against Watford on Tuesday evening.

The rangy defender has been unable to nail down a regular place in his favoured centre-back position, often filling in at right back, and United recently turned down substantially lower bids from two other clubs.