Mason, as the Video Assistant Referee, did not draw the guidelines to check for offside on Ivan Toney's equaliser.

"We would like to thank Lee for his dedicated service to the professional game and wish him all the best for the future," PGMOL said.

Following the draw with Brentford, Arsenal then dropped to second in the table after they were beaten 3-1 by Manchester City in midweek - a result that moved Pep Guardiola's side into top spot.

PGMOL chief refereeing officer Howard Webb contacted Arsenal to "acknowledge and explain the significant error" that occurred.

However, Gunners boss Mikel Arteta said the apology was not acceptable and added: "It wasn't human error, it was not understanding your job.

"It cost Arsenal two points that are not going to be restored so we are going to have to find those two points somewhere else in the league."

Bolton-born Mason was a Premier League referee for 15 years, overseeing 287 top-flight matches.