The lapse was a list of the 200 most stylish men of the century published in the March edition of GQ, which came out last week.
Mr Brown was sacked for including "The Nazis" and Rommel on his list.
It didn't help that Si Newhouse, patriarch and owner of GQ's publisher, Conde Nast, is Jewish. Conde Nast would only say yesterday that the Nazis editorial was a "mistake" and that Mr Brown was still editor. However, it is understood he is negotiating his leaving package.
The March edition of GQ attracted complaints from the Anti-Nazi League and Jewish organisations. It had already been a bad week for Mr Brown when the story broke.
The New York men's fashion shows are taking place and Mr Brown was supposed to be in attendance.
Unfortunately, Ronnie Newhouse, wife of Jonathan Newhouse, chairman of Conde Nast International, and another boss of Mr Brown's, is head of press at Calvin Klein.
She expected to be accompanied to some shows by Mr Brown, but he reportedly stayed in his hotel-room before leaving New York to holiday in Puerto Rico.
When the Nazis story broke, he was summoned back to London for a meeting with yet another boss, Nicholas Coleridge, head of Conde Nast UK.
Despite the poor style judgment, the most important factor in Mr Brown's falling-out with Conde Nast was the sales figures for the magazine.
Last week GQ posted its circulation for the last six months of 1998.
A modest increase had taken the title up to an average of 132,000 copies a month.
This is not what Conde Nast had in mind when it lured Mr Brown to GQ in May 1997. Then the title was selling 148,000 copies a month under the previous editor, Angus MacKinnon.
But Conde Nast was watching the lads' magazines Loaded and FHM take the market into the sales stratosphere, each selling more than 500,000 a month.
It wanted some of that action, so Mr Brown was brought in on a pounds 100,000- plus salary.
At the very least, Conde Nast wanted him to bring the title up to 250,000 or 300,000 a month.
In addition to sales, Conde Nast wanted colour. Before Mr MacKinnon, who is universally described as "donnish", the editor of GQ was Michael VerMeulen, a larger-than-life figure who died young from cocaine and alcohol abuse.
Mr Brown was supposed to bring "danger" back to the magazine.
That he certainly did. He gave up drinking shortly after his arrival when, in a post-lunch mood, he threw a champagne bottle through a window.
Drug and alcohol abuse had been part of the formula of Loaded, but it was also a part of Mr Brown's life.
He has described, as a teenager, sitting drinking on a park bench in his home town of Leeds to blot out the pain of his parents' separation.
After leaving school Mr Brown started his own music fanzines and travelled with bands. He got a job on the music magazine NME and rose to become its features editor.
When he failed to become the music weekly's editor, he left but was called back by its publisher, IPC, to talk about a new magazine idea. That idea was Loaded, a magazine about the best moments in your life, which, for a certain kind of twentysomething male, was football, women and drinking.
Loaded became a publishing phenomenon, increasing its sales by over 50 per cent every six months. The formula was copied by titles like FHM and Maxim and it scooped award after award.
When Conde Nast brought in Mr Brown, it promised he would not take the title down- market, but there has undoubtedly been a revolution. VerMeulen may have been colourful, but he had started his own theatre, was friends with David Mamet and John Malkovich and appreciated fine writing.
Mr Brown is credited with having "big ideas" and a flair for taking the ordinary man's thoughts and making them work in magazine form.
He is also acknowledged as a promoter of innovative talent. Those who have worked with him call him a charming tyrant.
But GQ has undoubtedly plunged down-market. The nipple count has increased, the writers have changed and there are a lot more bite-sized lists and snippets of writing.
Conde Nast has also thrown money at the magazine. The promotional budget has increased from around pounds 100,000 to over pounds 650,000. Almost every edition comes with giveaway CDs, CD-Roms, books and magazine supplements.
And yet the magazine is selling fewer copies than when Mr Brown took over. "It is the endless story of the maverick editor," says a rival magazine editor.
"Corporations see them being successful and think `we'd like some of that'.
"But then they become difficult and the corporate structure cannot take the baggage that comes with their talents."
Have Men's Mags Peaked?
THE SEEMINGLY unstoppable march of drink, sex and football across the shelves of newsagents ended last week after figures from the Audit Bureau of Circulations showed that sales of so-called lads' magazines appeared to have peaked.
FHM, the fourth best-selling magazine in the world, registered a 20,000 dip in sales over the last six months of 1998. The former trade title for the men's fashion world had risen from sales of 60,000 four years ago to a peak of 775,000 between January and June last year.
Loaded, which started the "laddish" revolution, also peaked. After years of increasing sales by 50 per cent almost every six months, in the second half of last year it put on just 945 copies a month, taking it to sales of 457,000.
Maxim, which increased sales by 21,000 to 321,000 copies a month, is also seeing its rate of growth slow down.