Arsene Wenger is "a dictator" whose time at Arsenal should have ended years ago, Stewart Robson told Sky Sports News.
The club's former midfielder, who played 210 times following his debut as a teenager in 1981, believes Wenger has a lack of tactical nous which is costing points every year.
Arsenal have made their worst start to a season under Wenger, but a large section of the support continues to back a manager who has twice delivered the Double and overseen an unbeaten league campaign during his 16-year reign.
Robson, though, told Sky Sports News Wenger's reluctance to listen to his backroom staff is behind the kind of defeat the Gunners suffered at League Two Bradford in the Capital One Cup.
He said: "It was a poor performance, but one I'm not surprised about. Time and time again Arsenal don't earn the right to play, and tactically (Bradford boss) Phil Parkinson showed he's a better coach than Arsene Wenger.
"I'm more embarrassed with the way Arsene Wenger conducts himself these days. He doesn't do any tactical stuff on the side of the field, they tell me he doesn't do too much work on the defensive side in training, yet he'll have a rant at everybody else.
"There's backroom staff that will challenge his decisions - Steve Bould, Neil Banfield, Terry Burton - but they can't challenge him because he's a dictator in many ways.
"Why isn't Steve Bould doing more coaching? Because - time and time again - I don't think Arsene Wenger sees the danger. When the team are making mistakes he doesn't rectify them, and the reason he doesn't rectify them is he doesn't know what the mistakes are.
"In my view it was time up three or four years ago. The fans have stuck by him, they always say 'in Arsene we trust', that can't be the case any more.
"Tactically Arsenal are all over the place at times, they're underprepared defensively, and if you have that you're always going to lose several football games in a season and not win trophies."