The agent of Gareth Bale says English football are sleepwalking themselves into disaster with planned changes to the game.
And Barnett has predicted that the Premier League may never see another Roman Abramovich take over a Premier League club again.
Barnett, whose 800-strong client list includes the likes of Tottenham attacker Gareth Bale and Aston Villa's Jack Grealish, said: “The salary cap in the Championship would be an absolute disaster. No good young players will want to go to those clubs. It's heading for doom.
“The standard will drop dramatically and I guarantee that if we didn't have these spending rules, you would see big hitters buying Championship clubs.
“Abramovich has done a great job. When he came in, Chelsea were going broke, the league was struggling, he put money into Chelsea, gave money to other clubs and transformed the game and you could have the same in the Championship but for these rules.
“Abramovich was the best thing to ever happen to the Premier League, it's now the best league in the world and yet it's a terrible trait in England that we build things up to knock them down."
Barnett also fears the worst on Brexit and says the impact on football was already felt in January when there was a record low spent on transfers.
“Brexit is the biggest threat to English football," said Barnett. “Look at Wolves, they've been so successful and yet would they get in now? There's players who could have saved West Brom but they can't get work permits. I truly believe European players have helped British players so much.
“I remember when Patrick Vieira came into Arsenal, I was sitting with John Hartson who was my client while Vieira was sitting with some people and he ordered a salad and water. I'm not going to say what John had… I said: 'Look at him…' John said: 'I know it's disgusting - I'll have a word!'
“I'm telling you - the young British players are the best of my lifetime and that's because they've been brought up and learned from the best. If you reduce the standard, you damage other players."
