Seven weeks out from the first Test at Edgbaston, he has fired the first shot across Australia's bow with his bizarre claim.
In a lengthy interview, he also predicted Australia will not know how to react to England's up-tempo style and that the visitors' batters could struggle.
But regardless, Broad said the fact England had to endure a quarantine period and the teams spent part of the tour in a bubble meant it was not a true contest.
"Nothing was harsher than the last Ashes series," Broad told the Daily Mail. "But in my mind I don't class that as a real Ashes. The definition of Ashes cricket is elite sport with lots of passion and players at the top of their game.
"Nothing about that series was high-level performance because of the Covid restrictions. The training facilities, the travel, not being able to socialise. I've written it off as a void series."
Broad's comments are not the first complaints from the English camp about that series. There were suggestions before the tour began some players would withdraw if families were not granted exemptions to enter Australia. England then grew frustrated by wet weather washing out almost all of their preparations.
Then-coach Chris Silverwood was also unhappy with his quarantine conditions after he was one of several support staff to test positive to Covid-19 during the Boxing Day Test. Covid is considerably less likely to play a significant role in the lead up to this year's Ashes.
England's 'BazBall revolution' of attacking Test cricket is instead likely to dominate the headlines before the series, with Broad warning Australia's batters not to try to emulate the home side's style.
"It would be great for us if Australia try to take us on at our own game," Broad said. "If we can get them playing in a slightly different style they could make mistakes and that would be brilliant for us.
"Steve Smith, Marnus Labuschagne and Usman Khawaja are all guys who like to bat time and accumulate. So if we can nibble away at them and just get them thinking, 'Why are we not scoring quicker? Why are we not moving the game forward?'.
"I'd love Smith to dance down the track and sky one to mid-off early doors. That would be classic."