Rangers told Willie Collum won't be bullied out of the game as refs chief leaves Celtic derby return on

Scotland's head of referees has admitted Willie Collum dropped a clanger in the last Old Firm game - but insisted Rangers won’t be allowed to bully the whistler out of the game.

Refs chief Crawford Allan launched a staunch defence of the controversial official after meeting with all top flight clubs yesterday for the second mid-season review of VAR across the Premiership. Allan revealed that the derby day cock-up was one of 13 separate incidents which an independent review panel believe were botched by VAR over the second part of the season - rocketing up from just three mistakes in the first round of fixtures.

The Ibrox club reacted furiously when Collum dismissed a possible penalty kick from Clydesdale House despite slow motion replays showing Alistair Johnston had handled the ball inside Celtic ’s box. It was only after Collum’s intervention that subsequent graphics proved the award would not have stood in any case as Rangers striker Abdallah Sima had drifted offside moments earlier during the attacking phase of play (APP).

But that didn’t stop the Ibrox club demanding showdown talks with the SFA during which they called for Collum to be blackballed from officiating at any of their future matches. Last week Rangers boss Philippe Clement publicly distanced himself from that war footing and welcomed Collum’s appointment for his side’s Scottish Cup tie against Ayr United.

But now Allan has admitted that Collum got it wrong. He said: “It’s hard to say he made a mistake because he didn’t make a factual process error. It was a subjective decision that Willie made and he is entitled to that.

“Would I have preferred if the handball had been examined through to an APP? Yes.

“But I am not going to say that Willie has done