Their pleas for calm came after the Animal Liberation Front, thought to have about 200 activists operating on the fringes of the welfare movement, said it was not going to issue "any idle threats".
"But what has happened to Jill has intensified our anger... Jill's death will not be in vain. Jill realised that we are dealing with a holocaust of animals in this country. She was a person who agreed with confrontation."
ALF members are thought to have been involved in an attack on the home of Phoenix Aviation's two directors on Thursday afternoon.
Other sources inside the animal rights movement confirmed that the initial success of peaceful protest against the trade convinced the ALF and similar groups to stick to non-violent activities. The death of Ms Phipps and the determination of exporters tokeep the trade flowing may convince the extremists to take more direct action.
Mainstream campaigners, though frustrated by the "lack of political progress" on banning the trade, appealed for the protesters to remain peaceful.
Compassion in World Farming said the only effective way to stop the trade was through peaceful protest. "Peaceful protest and reasoned argument are very powerful forces and it would be foolish for the government to ignore them," said Phil Lymbery, spokesman for the organisation.
Other veterans of the campaign, however, said they are willing to go further and sanctioned civil disobedience to force the exporters to stop.
Campaigners at Shoreham in West Sussex, fresh from a victory over the port, which has now decided to stop the livestock trade, said active protest is the most effective form of action. The Shoreham protests were largely non-violent but more than 1,000 riot police were required to ensure the livestock lorries could enter the port.
"The port authority originally thought the protest would be just Compassion in World Farming singing carols at the gates - but who takes any notice of that kind of protest?" said Betty Clarke, a hardened campaigner from Shoreham.
Now the Shoreham protesters are planing to organise coaches to swell the demonstrations at Plymouth and Brightlingsea. Dave Clarke, also a veteran of Shoreham, said that if the protesters keep "closing down the ports then the trade will eventually stop".Reuse content