The News of the World is alleged to have hacked and then deleted voicemails on the mobile phone of murdered teenager Milly Dowler, interfering with police inquiries into her disappearance in 2002, according to an investigation by the Guardian.

Ford says it will cease placing advertising in the News of the World until the outcome of an investigation into phone hacking there has been announced, but will continue to advertise in other News International titles.

A Ford spokesman says: “Ford is a company which cares about the standards of behaviour of its own people and those it deals with externally. We are awaiting an outcome from the News of the World investigation and expect a speedy and decisive response.”

Halifax, Npower and T-Mobile have also confirmed they are reviewing their advertising options with the paper.

A spokesman for Npower says: “We note the concerns which have arisen on the back of fresh allegations of phone hacking against the News of the World. We are currently reviewing our options.”

Activists have published lists online of recent News of the World advertisers, allowing users to tweet and e-mail the companies to ask whether they will be reconsidering their advertising campaigns with the newspaper.

A group of leading journalists, MPs and academics have also formed a campaign, dubbed Hacked Off, calling for a public inquiry into the phone hacking allegations at the Sunday tabloid.

Other advertisers with the newspaper have yet to comment on the status of their relationships with the News of the World.

Virgin Media, Tesco and Brand Alley all say they are awaiting the outcome of the investigation before taking further action.

The Co-operative, which advertised in last week’s News of the World, has said it has no plans to pull any advertising, despite the public outcry against the paper.

A spokesperson for the Co-operative says: “These are allegations. We have no plans to withdraw our advertising.”

A BT spokeswoman says the company is “not commenting” on the situation.

Earlier this year, News International apologised for hacking into the phones of celebrities including actress Sienna Miller and MP Tessa Jowell and set up a fund to compensate the victims.

News International did not respond to a request for comment in time for publication.