The 36-year-old former Norwich and Celtic defender will be assisted by first-team coach Martin Hunter while the club search for a suitable replacement for Boothroyd.

The Hornets are currently in 21st position in the Coca-Cola Championship following the 4-3 defeat by Blackpool at Vicarage Road last Saturday and face Swansea in their next fixture on Sunday.

The move to part company with Boothroyd came after a disastrous 12 months at Vicarage Road, with the Hornets picking up just 12 wins in the last 50 league matches to fall from promotion contenders to relegation strugglers.