It must have seemed a routine assignment for one of the Daily Mail's star columnists: a catty take on the death of Boyzone star Stephen Gately which pandered to the prejudices of its readers.

But the paper was forced to withdraw advertising from part of its web site after an extraordinary internet campaign prompted by a Jan Moir article questioning the role Gately's lifestyle and sexuality played in his death last Saturday.

Marks & Spencer was among the major firms whose adverts were taken down following outrage at Moir's article, headlined "There was nothing 'natural' about Stephen Gately's death". Complaints poured in to the Press Complaints Commission at the fastest rate in its history, causing its website to crash. The Mail also removed adverts for Nestle, Visit England, Kodak and National Express.

Moir wrote that the circumstances surrounding Gately's death at 33 "are more than a little sleazy" and told how he and his civil partner, Andrew Cowles, had taken a Bulgarian man to their flat in Mallorca after a night clubbing, and that Gately reportedly smoked cannabis on the night he died.

She said: "Under the carapace of glittering, hedonistic celebrity, the ooze of a very different and more dangerous lifestyle has seeped out for all to see."

A postmortem on Tuesday showed that Gately died of natural causes. A court official in Mallorca said the singer suffered a pulmonary oedema, an accumulation of fluid on the lungs.

Moir's article, published on the eve of the singer's funeral in Dublin, sparked a storm of protest on the internet, led by Stephen Fry and Derren Brown on the messaging site Twitter, on which they have a combined following of almost one million.

Fry wrote: "I gather a repulsive nobody writing in a paper no one of any decency would be seen dead with has written something loathsome and inhumane. Disgusted with Daily Mail's Jan Moir? Complain where it matters. She breaches 1,3,5 & 12 of the code."

By this evening the PCC had handled 1,000 emails and calls complaining about inaccuracies, insensitivity to Gately's family and alleged homophobia. The PCC's deputy director, Stephen Abell, said officials contacted Boyzone's PR company yesterday "to let them know what had happened and to make themselves available if they wanted to complain".

The names and numbers of the corporate advertisers on the article's web page were posted on a Facebook group called "The Daily Mail should retract Jan Moir's hateful, homophobic article".

"We have asked the Daily Mail to move our advert away from the article," said a spokesman for Marks & Spencer. Asked why, he said: "That is a matter for the Daily Mail." A spokesman for Nestle said it had received several complaints, and added: "The views in the article are not shared by Nestle. We have always emphasised the importance of mutual respect and tolerance."

James Bromley, Mail Online managing director, told New Media Age magazine that the decision to remove the ads was taken by Mail Online after it "saw the strong reaction".

As outrage grewtoday, the Mail changed the headline on Moir's piece to "A strange, lonely and troubling death …" and late this afternoon Moir published a clarification of her article.

"When I wrote that 'he would want to set an example to any impressionable young men who may want to emulate what they might see as his glamorous routine,' I was referring to the drugs and the casual invitation extended to a stranger," she said. "Not to the fact of his homosexuality. In writing that 'it strikes another blow to the happy-ever-after myth of civil partnerships' I was suggesting that civil partnerships – the introduction of which I am on the record in supporting – have proved just to be as problematic as marriages."

She questioned how many of those complaining about her piece had read it completely and said that she had been subject to "a heavily orchestrated internet campaign".

"I think it is mischievous in the extreme to suggest that my article has homophobic and bigoted undertones," she said.

At times, reaction on the internet became disturbing. Moir's home address was reportedly posted, and the false allegation that the Daily Mail had claimed Gately had been murdered by his partner was repeated on Twitter.Moir has previously employed innuendo when commenting on homosexual public figures. In an article in August about Peter Mandelson, the business secretary, she wrote that "with his blue suede shoes, his peach mansion and his green tea devotionals, he is like a rock star camping it up on a farewell tour", and said he has spent years "clawing his way up the soil pipe of politics".

Gately's body arrived back in Dublin from Palma airport today. The remaining members of Boyzone are expected to sing at his funeral at St Lawrence O'Toole Church.

Gately came out in 1999 after a security guard for Boyzone went to a tabloid newspaper about his sexuality.