A Scottish oil company's attempt to stop Greenpeace activists tweeting about a protest and posting pictures of people dressed as polar bears on the internet has backfired with hundreds of people around the world breaking the injunction on behalf of the environment group.

It is the first such injunction to be issued since the row in May over the flouting of super-injunctions taken out by celebrities by users of Twitter.

Cairn Energy, the company now exploring for oil and gas off the coast of Greenland, was granted an interim injunction on Monday after 17 people, some dressed as polar bears, entered their Edinburgh headquarters and staged a sit-in, demanding a copy of the company's oil spill response plan to drilling in the Arctic.

The Scottish court order prohibits the environment group "disseminating, printing, uploading, sharing, copying or otherwise publishing any images, photographs, pictures or other material (or copies thereof) taken or recorded by Greenpeace activists present within 50 Lothian Road, Edinburgh on or around 18 July 2011."

A Greenpeace spokesman said: "We have had to delete certain tweets. The injunction says 'any images or material taken inside Cairn's offices has to be deleted'. That means all blogposts and tweets done during the protest have to come down and any pictures sent out by us removed. We have had to warn picture desks around the world."

But hundreds of people have begun posting the pictures on their personal Facebook and Twitter accounts.

Spreading photographs of Greenpeace protesters dressed as polar bears across Twitter and social media websites could stir up a fresh challenge to the courts' system of injunctions, lawyers have warned.

"If people start tweeting and putting the pictures on Facebook they could be in contempt of the Scottish courts," said Jennifer McDermott, head of media and public law at the London solicitors Withers LLP.

"I suppose they are worried that any photographs taken may show pictures of employees or confidential papers. The protesters can go back and challenge the injunction. It's only an interim injunction.

"But if you go into someone's private property it's difficult to get it lifted," McDermott, who was involved in the Spycatcher case in the 1980s. "They have appeared in a sheriff's criminal court.

"I'm surprised that Cairns' lawyers are not getting an injunction in [England] but if you know about an injunction and try and defy it ... [you would] be in contempt of the Scottish courts."

Whether the injunction can be enforced abroad is questionable. The same issue emerged during the row over privacy superinjunctions this summer where names of celebrities and premiership footballers circulated across Twitter and the internet in the face of mounting legal frustration.

The attempt to prevent Greenpeace using social media to report the protest has echoes of the Ryan Giggs affair, when thousands of people broke a super injunction. Cairn's wide-ranging order is believed to be the first time that any group has been told to retract posts and photographs.

Greenpeace on Tuesday claimed it was being gagged. "Cairn Energy is using its legal muscle to try and gag us from telling the truth about their dangerous oil drilling in the fragile Arctic environment," said Greenpeace's executive director, John Sauven. "The company is clearly worried that our volunteers may have got their hands on their secret Arctic spill response documents and now they are determined to continue their cover up by any means they can – even if that means impinging on important freedoms of expression."

"Cairn's bosses can use their expensive lawyers to try and shut down our peaceful protests using chilling legal manoeuvres, but we will continue to campaign to protect the Arctic from reckless corporations who see the melting of the polar ice as a business opportunity."

A spokesman for Cairn said: "Cairn's purpose is not in any way, shape or form to shut down or 'gag' debate – indeed we have been on the record about people's clear right to protest for two years now. The step taken has been to protect confidential information which Greenpeace people have or may have accessed during a near eight-hour occupation of private offices. This is a duty to all sorts of people including employees, partners and shareholders. Of course we are not going to take action where none is warranted."