Mark Clattenburg has been the subject of a complaint from Saints, who claim the referee verbally abused England midfielder Adam Lallana during their 2-1 defeat to Everton last Sunday.
The referee is no stranger to controversy and here Echo Sport looks back at six other incidents when he has found himself in the spotlight.
JANUARY, 2005 - PEDRO MENDES 'GOAL' NOT GIVEN.
Clattenburg failed, along with his assistants, to spot Tottenham midfielder Mendes' shot had been fumbled clearly over the line by Manchester United goalkeeper Roy Carroll in a match at Old Trafford and a goal was not given.
OCTOBER, 2007 - TONY HIBBERT SENT OFF.
The Durham referee sent off Everton defender Hibbert in a Merseyside derby. After initially appearing to be about to show him a yellow card, Clattenburg seemed to change his mind and pulled out a red after a brief exchange with Steven Gerrard. He later did not send off Dirk Kuyt for a two-footed lunge at Phil Neville. Clattenburg did not referee another Everton match until 2012.
AUGUST, 2008 - SACKED OVER BUSINESS DEALINGS.
He was suspended pending a probe into his business affairs following allegations he owed £60,000 as a result of a failed venture. He was pulled out of the FA Community Shield clash between Manchester United and Portsmouth as a result and later sacked by the Professional Game Match Officials board. In February 2009 he was reinstated as a Select Group Referee on appeal, but suspended for eight months from August 6, 2008, - the date of his original ban - for ''issues relating to his private business affairs''.
DECEMBER, 2009 - CRAIG BELLAMY ACCUSATION.
It is alleged, in a match between Bolton and Manchester City, that Clattenburg asked the City bench: ''How do you work with Craig Bellamy all week?'' He then sent Bellamy off for two yellow cards in the game.
OCTOBER, 2010 - NANI GOAL STANDS.
Clattenburg correctly, if controversially, allowed a goal to stand between Manchester United and Tottenham when Nani tapped the ball in after Spurs goalkeeper Heurelho Gomes put the ball down, believing his side had a free-kick. Clattenburg had not blown his whistle.
OCTOBER, 2012 - CLEARED OF RACIST ABUSE CLAIM.
Clattenburg was accused of using "inappropriate language" towards Chelsea midfielder John Obi Mikel during their 3-2 defeat to Manchester United - a game in which Clattenburg sent off Branislav Ivanovic and Fernando Torres, while replays showed United's winning goal was offside. The allegations were the subject of investigations from both the FA and the Metropolitan Police, and Clattenburg was ultimately cleared. Instead, Mikel was punished with a £60,000 fine and a three-match ban for threatening Clattenburg after the match.