Max Verstappen's father, Jos, has launched another stinging attack on Red Bull and team principal Christian Horner following design chief Adrian Newey's departure and the emergence of McLaren as serious contenders.

Lando Norris won Verstappen's home Grand Prix by a 22-second margin last time out, with Red Bull once again short of pace compared to their McLaren counterparts.

And Jos Verstappen has lamented the "serious" situation arising within the team, who are having to look over their shoulder in fear of losing out on titles.

"You can't sugarcoat it anymore, the situation is serious," Jos told German outlet Bild. “Max won't be satisfied with having a car like that. Now it's up to Horner to get the team back on track.

"More than 20 seconds is a very big disappointment. Max never had a chance to win. But that's not surprising when you reverse-engineer the car."

Red Bull opted to use older parts of their car that had been utilised earlier in the season, but after failing to secure a single victory in the past five races, Jos insisted that decision was dumbfounded.

"That says it all,” he added. “The team took the wrong turn several times. Internally, you should hold a mirror up to yourself and not always gloss over everything. It is time – if it is not already too late – to question ourselves. The good people are leaving the team. I'm very unhappy with what's happening."

Newey, widely considered to be one of the greatest F1 minds in the sport's history, is expected to join one of Red Bull's rivals this season.

And after calling for Horner to lose his job at the beginning of the season, Jos does not hold faith that the chief can turn the team's fortunes around without the 65-year-old.

"I'll be surprised, but at the moment I'm saying no,” he said. “A lot has to happen. The whole spirit has to change."

Horner and co will get the chance to move their star driver's father wrong this weekend at Monza, where they secured a one-two last year in a season of dominance before the wheels began to fall off.

But McLaren and Norris will believe that they can close the gap even further to Red Bull, with the Brit now just 70 points behind his rival in the drivers' standings and the team only 30 points behind in the constructors championship.