Professional Game Match Officials Limited (PGMOL), the body responsible for match officials across English football, has admitted two "significant errors" with VAR offside decisions -- one which went against Arsenal that could have implications on the Premier League title race.

Arsenal drew 1-1 at home to Brentford on Saturday, with Ivan Toney earning a point for the visitors with an equaliser in 74th minute. The VAR in that game, Lee Mason, instigated a review for a possible offside in the buildup against Ethan Pinnock, which was cleared, but he failed to identify Christian Norgaard, who assisted the goal for Toney, had came back from an offside position.

It meant the offside lines were not applied by Mason, and the goal was allowed to stand. The result leaves Arsenal six points clear of Manchester City, with the two teams meeting at the Emirates on Wednesday.

It is the second major VAR error involving Mason and Arsenal, with Gabriel Martinelli's disallowed goal at Manchester United, when the score was 0-0 in a game the Gunners lost 3-1, ruled by the independent assessment panel to be an incorrect intervention.

Brighton & Hove Albion were also on the end of a VAR error in their 1-1 draw at Crystal Palace when Pervis Estupinan's goal was ruled out for offside. PGMOL has admitted this decision was also wrong, with the offside line placed in the wrong position by the VAR, John Brooks, and the Hawk-Eye technology operator.

"PGMOL can confirm its Chief Refereeing Officer Howard Webb has contacted both Arsenal and Brighton & Hove Albion to acknowledge and explain the significant errors in the VAR process in their respective Premier League fixtures on Saturday," read a statement issued by PGMOL. "Both incidents, which were due to human error and related to the analysis of offside situations, are being thoroughly reviewed by PGMOL."

Howard Webb, PGMOL's new chief refereeing officer, is promising greater openness and transparency over decision-making -- including admitting when major mistakes have been made. Two weeks ago, PGMOL admitted Fabinho should have been sent off for his challenge on Brighton & Hove Albion forward Evan Ferguson in an FA Cup tie.