Barry Ferguson has shared what he thinks of Willie Collum taking charge of Rangers vs Ayr United in the Scottish Cup this evening. The experienced whistler will be the man in the middle at Ibrox as both sides meet to battle for a place in the quarter-final of the competition. Collum has enraged Rangers fans over the years but it all came to a head during and after the Old Firm derby defeat against Celtic at Parkhead. He was on VAR duty and miraculously failed to recommend an on-field review to Nick Walsh after Alistair Johnston clearly handled inside the penalty box. Abdallah Sima was later sh…