Animal rights activists involved in an intimidation campaign against GlaxoSmithKline shareholders could have their e-mail accounts suspended, MSN, the Hotmail service operator, said on Tuesday.

The Campaign Against Huntingdon Life Sciences, an animal rights group, has sent letters to individual GSK shareholders warning them that their details will be posted on the internet unless they sell their shares within two weeks. They are also told to e-mail the protesters to tell them they have done so.