Pharmaceuticals giant GlaxoSmithKline has launched a bid to expel animal rights protesters from the doors of 18 of its bases.
The Brentford-based multi-national claims protesters have waged a campaign of harassment and intimidation against its employees, including violent attacks on workers' vehicles and graffiti attacks on their homes.
Campaigners are protesting against Glaxo's use of research from Cambridgeshire-based Huntingdon Life Sciences, a company which has been at the centre of animal rights supporters attention.
Glaxo's lawyers took the case to the High Court in London last week to ask a top judge to grant an injunction to curtail the campaign by creating "exclusion zones" around their premises and banning harassment of workers.
Paul Girolami, representing the company, described how a senior member of staff had found the word "paedophile" daubed on his home, while another was sent a letter, purporting to be from the police, in which he was accused of being a rapist.
Protests outside the company's bases - including those in Uxbridge and Greenford - had also turned sinister, with campaigners climbing onto workers' cars and shouting at them through megaphones.
Lawyers acting for the company were granted an emergency, temporary injunction earlier this month and on Thursday asked top judge, Mr Justice Teare, to extend the order, which, if granted, would restrict protests at 18 of the company's sites.
Mr Girolami asked the judge to make the order against animal rights campaigners, Greg Avery, representing the Stop Huntingdon Animal Cruelty (SHAC) group, and Robin Webb, representing the Animal Liberation Front (ALF).
The proposed order would prevent any campaigners from "assaulting, harassing, molesting, threatening or otherwise interfering" with any workers or their families and from knowingly "picketing, demonstrating or loitering" within 50 yards of their homes.
It would restrict protests at the company's premises to once every 28 days, between 10am and 4pm, and with a maximum of either 20 or 30 participants, depending on the particular site. Megaphones, klaxons, sirens, whistles, drums and amplifiers would also be banned.
But Mr Avery, who is a spokesman for the SHAC group, which has been protesting against animal cruelty since 1999, argued that no order should be made against his group, since it was already doing all it could to make sure its protests remained within the law.
He said the vast majority of the evidence of illegal activity linked to the protests had nothing to do with SHAC, which fully cooperated with police, and could be attributed to the ALF. Only half of the 18 sites had even experienced protests of any kind, he added.
"Where is the sense in sending the message out that, if you organise demonstrations in conjunction with the police, you are going to end up with an injunction?" Mr Avery said.
"You tell them where, you tell them when, you tell them how many - what sort of message does that send out?"
Adjourning the case to consider his decision, Mr Justice Teare said: "I will obviously have to reserve my judgment in this matter and, pending the giving of the judgment, the injunction remains in place."
The judge gave no date for when he will rule on the case.