"We've signed Nigel because he is an experienced player who will add competition to our central midfield positions," West Ham coach Alan Curbishley told the club's website.

The 28-year-old Scottish international is West Ham's second signing in the January transfer window following Luis Boa Morte, who joined from Fulham.

The Hammers are third from bottom in the Premiership table with 18 points from 22 games.

Curbishley has been appointed West Ham manager in December, succeeding Alan Pardew.