The law firm at the centre of an unprecedented attempt by a British oil trading firm to prevent the Guardian reporting parliamentary proceedings is to be reported to the Law Society, it emerged today.

Gordon Brown described the case as "unfortunate" when he was quizzed about the matter during prime minister's questions in the Commons today.

And he said the justice secretary, Jack Straw, had spoken to the parties concerned to try to resolve the issue.

Brown spoke after Conservative Peter Bottomley told MPs he was reporting Carter-Ruck, the law firm that acted on behalf of Trafigura, to the Law Society, saying that no lawyers should be able to inhibit the reporting of parliament.

"I will be seeking their advice on whether it is proper for any lawyer to purport or intend to inhibit the reporting of parliament," Bottomley told the Guardian.

"It is the job of the press to make aware to all what is known by a few. Any court action which inhibits that should be approved at a very high level, with full justifications, and in normal circumstances, should not be made in secret."

Carter-Ruck was accused of infringing the supremacy of parliament yesterday after it insisted that an injunction obtained against the Guardian prevented the paper from reporting a question tabled on Monday by the Labour MP Paul Farrelly.

Farrelly's question was about the implications for press freedom of an order obtained by Trafigura preventing the Guardian and other media from publishing the contents of a report related to the dumping of toxic waste in Ivory Coast.

In yesterday's edition of the paper, the Guardian was prevented from identifying Farrelly, reporting the nature of his question, where the question could be found, which company had sought the gag, or even which order was constraining its coverage.

But numerous users of the social networking site Twitter posted details of Farrelly's question and by yesterday morning, the full text had been published on two prominent blogs as well as in the magazine Private Eye.

Carter-Ruck withdrew its gagging attempt by lunchtime, shortly before a 2pm high court hearing at which the Guardian was about to challenge its stance, with the backing of other national newspapers.

Yesterday Carter-Ruck, whose partner Adam Tudor has been representing Trafigura, issued a press release conceding: "The order would indeed have prevented the Guardian from reporting on the parliamentary question which had been tabled for later this week." But the firm said the Guardian's reporting on the issue had been "highly misleading".

The firm added: "There is no question of Trafigura seeking to gag the media from reporting parliamentary proceedings, and the parties have now agreed to an amendment to the existing order so as to reflect that."

Carter-Ruck has been contacted for comment.