Seven animal rights activists - including one from Croydon and another from Chiswick - are due to be sentenced for blackmailing companies who supplied Huntingdon Life Sciences.

Gerrah Selby, 20, from Chiswick and Gavin Medd-Hall, 45, from Croydon along with Heather Nicholson, 41, from Eversley, in Hampshire, Daniel Wadham, 21, of Bromley orchestrated the campaign which ran between 2001 and 2007, Winchester Crown Court heard.

The maximum sentence for the offence is 14 years' imprisonment.

Three other people - Gregg Avery, Natasha Avery and Daniel Amos - pleaded guilty to conspiracy to blackmail at Winchester Crown Court, Hampshire, last month.

The hierarchy of the group - called Stop Huntingdon Animal Cruelty (Shac) - used a number of tactics: hoax bombs parcels; criminal damage; threatening telephone calls; and false claims that the managers of the companies were paedophiles; in a bid to force them to cut links with the animal testing company.

The aim was to target suppliers or any company with a secondary link with Huntingdon Life Sciences (HLS), based in Cambridge.

An example of their intimidation included the sending of used sanitary towels in the post, saying they were contaminated with the Aids virus.

In another example, roads outside the homes of company managers were daubed with words like "puppy killer".

The blackmail would only stop when managers put out a "capitulation statement" to Shac saying they would not supply HLS, which conducts animal testing for the pharmaceutical industry.

The defendants were also linked to criminal activity in Europe and America, targeting companies there.