The campaign against the News of the World newspaper, which has this morning led to a growing number of brands reviewing their advertising, has seen a torrent of tweets attacking the News International-owned title.

The hashtag #saynotonotw is one of the top trending topics in the UK, as consumers call for a boycott this Sunday of the News of the World, as a more formal organised online campaign against the paper is organised.

An online petition has been launched calling for a public inquiry “with full powers to call for papers and summon witnesses can explore the full range of issues involved”.  PR Week is also reporting that the Media Standards Trust is calling for a public inquiry.

Three left of centre blogs, Liberal Conspiracy, Political Scrapbook and Left Foot Forward are coordinating the online campaign.

A Boycott News Of The World Facebook group has been launched has more than 4,000 members. A second Facebook group asking advertisers to boycott the News of the World this coming Sunday has around 650 members.

Yesterday, a list of advertisers was published online that users could tweet at and ask them to pull their advertising.

An online brand targeted the paper’s advertisers is also gathering steam. Thomas Cook, Sainsbury’s, T-Mobile, Halifax and First Choice are the latest big name brands to review their advertising support for the News of the World, in light of the phone-hacking allegations, as Brand Republic reports this morning.

Last night Ford became the first major advertiser to pull its News of the World advertising following the Milly Dowler allegations

This morning Mumsnet has also said it intends to pull its Sky campaign in protest at NotW following increasingly vociferous calls from its influential community that it should not be associated with a Murdoch-owned organisation.

The editor of The Times, a sister paper to News of the World, James Harding called the alleged actions ‘indefensible’.

The volume of tweets and the anger will certainly be a worry. One Twitter posted “@Hardisteee Looks like the demise of #NOTW from my Twitter feed this morning… #saynotonotw”.

However, the rest will come on Sunday and whether the shocking revelations will deter people from buying the nation’s top selling tabloid newspaper with a circulation of 2,664,363.