FORMER referee chief Keith Hackett has admitted that he thinks Stuart Armstrong should have seen a straight red card for his high boot on Aymeric Laporte.

The Scottish international was booked for the challenge on goalscoring defender Laporte, and escaped further punishment during a VAR review in the 1-1 draw with Manchester City.

When the match was reviewed later on BBC, pundit Danny Murphy revealed that the PGMOL – who manage all referees in England’s top flights – gave an official explanation for why it was only a yellow.

He said they had insisted it lacked the “intensity” needed for it to be a straight red card.

Daily Echo: Stuart Armstrong left studs on Man City defender Aymeric Laporte (Pic: Stuart Martin)Stuart Armstrong left studs on Man City defender Aymeric Laporte (Pic: Stuart Martin)

But Hackett refutes that suggestion and thinks the 27-year-old should have faced harsher punishment.

He told Football Insider: "I’m clear, the boot is high, it’s come down and raked his opponent, it’s a red card.

“We had a challenge that endangered the safety of his opponent. The player was moving forward so there was forward movement, the player could have avoided doing that. The player has a duty of care to his opponent.”

He continued: “This is a foul and it must be given. Tell the explanation to the player who is probably having his leg bandaged up this morning.

“I listened to it and thought ‘here we go again’. The PGMOL are great now at coming up with these one-liners that are incredible and have no relationship to the law.

“I guess it was a press guy rather than a referee.”

If Armstrong was sent off by referee Simon Hooper, he would have been handed a three-match ban and would have missed Saints’ FA Cup clash with Coventry.

He would then have been absent for two big away trips to Tottenham and Manchester United in the Premier League.

One of the most respected officials in the game, Hackett, 77, was a FIFA-list referee for 10 years and had a lengthy career in the Football League and Premier League.