The Premier League referee Mike Dean has been demoted to the Championship this weekend, as a punishment for his erratic display in Manchester United's 2-1 defeat by Chelsea at Old Trafford last Saturday.

Simon Beck, an assistant referee in the same match, will join him in the second tier after failing to raise his flag when Didier Drogba was clearly offside for Chelsea's second goal. The pair will take charge of Bristol City's home game against Swansea on Saturday.

After the United vs Chelsea match the two officials were criticised by Sir Alex Ferguson for their "poor, poor performance". United's manager was also unsparing in his match report to the Premier League. However, Professional Game Match Officials Limited decided the mistakes were serious enough to demote Dean and Beck without any interference from Old Trafford.

Beck has not been informed when he will next be involved in a Premier League match and is missing from the list for next week's midweek fixtures. Dean, a member of the elite group of Fifa referees since 2002, will be the fourth official for Wigan Athletic's home game against Portsmouth on Wednesday 14 April.

It follows Dean's failure to award penalties for United, when Yuri Zhirkov tripped Park Ji-sung, and Chelsea, when Gary Neville barged into Nicolas Anelka. The 41-year-old also allowed Federico Macheda's goal to stand, rather than awarding a handball against the teenager.

Dean's appointment for such an important game had come under scrutiny because of his performance in Burnley's 1-0 defeat by Blackburn Rovers the previous weekend.

Brian Laws, the Burnley manager, said Dean had been "conned" into awarding a match-winning penalty when Martin Olsson went to ground despite there being no contact from the goalkeeper, Brian Jensen. Olsson has since admitted that he went into the game aware of Dean's reputation for awarding penalties.

Laws said Dean's subsequent appointment to the biggest match of the Premier League season to date was "mad".

After the loss to Chelsea, Ferguson said: "When I saw it was Mike Dean I did worry, I have to say."