A regional daily has won a major victory in its four-year battle to obtain secret government documents about a controversial company takeover in the 1980s.

York confectioners Rowntree was bought out by Nestle in 1988 and the matter discussed at the highest reaches of Margaret Thatcher’s government at the time.

Now a tribunal has dismissed the Cabinet Office’s appeal against the Information Commissioner’s Office ruling that ministerial papers relating to the discusions should be made public.

In a victory for York-based daily The Press, tribunal chairman Judge John Angel said the public interest favoured disclosure of the documents, and ordered that they should be disclosed within 30 days.

Mr Angel also ordered the Cabinet Office to confirm or deny whether it held information about Cabinet discussions of the Rowntree takeover, which went through in the face of then then Yorkshire Evening Press’s Hands Off Rowntree campaign.

More than 13,500 readers signed a petition against the deal while 1,500 protesters staged a rally outside Parliament.

News editor Gavin Aitchison, who gave evidence at the hearing in London last month said:  “We are obviously very pleased with the Tribunal’s decision.

“The 1988 takeover of Rowntree by Nestle was a huge moment in modern York history and there is an inherent public interest in people being able to see how the government of the day handled the matter.

“The case for keeping these documents secret had been seriously diminished, not least because the current government has already announced it is replacing the 30-year-rule with a 20-year-rule.

“It remains to be seen whether the Cabinet Office will appeal this latest decision, but we have spent a long time trying to access documents and very much hope the end is in sight.”

The Cabinet Office still has 28 days to apply to the tribunal to set aside its decision if it considers there was any ‘procedural irregularity’ and it can also appeal to an Upper Tribunal if it believes there has been an ‘error of law’.

Former Cabinet Office director Jeremy Pocklington had told the hearing he believed disclosure would have a ‘chilling’ effect on current ministers in their future discussions on similar issues, potentially inhibiting them from putting forward their views.

But Judge Angel said there was a ‘very weighty’ public interest in transparency and openness in this case and in whether the quasi-judicial role of Lord Young, the minister who allowed the takeover, was not compromised by improper political or other pressure.

“There is a very significant public interest, including for researchers of social, political and industrial history, in reading the impartial record of contemporaneous communications,” he said.

The Rowntree deal was particularly controversial because Nestlé itself was effectively protected by Swiss law from such takeover attempts, but the Thatcher government refused calls to refer the matter to the then Monopolies and Mergers Commission.

The Press originally sought the cabinet documents in 2008 under the Freedom of Information Act but some were withheld, and its subsequent appeal failed.

The newspaper re-applied in 2010, the Cabinet Office refused again but the Information Commissioners subsequently ruled in the newspaper’s favour, prompting the appeal.