Mr Justice Sales confirmed today (18 June) the Public and Commercial Services union was right to challenge the way the terms of the civil service compensation scheme, which governs redundancy payments, were slashed.

The decision quashes an amendment to the scheme that the previous government had claimed was effective from 1 April, and requires the new government to enter into negotiations with PCS if it wants to change the scheme in future.

While the judge quashed the detrimental changes to the scheme, he retained elements - relating to protection against age discrimination - that provide improvements. The union says this shows it was not opposed to change on principle, but that any alterations had to be fair and agreed.

The union’s challenge, by way of a judicial review, was heard over two days in April and the judge ruled on 10 May that the previous government had acted unlawfully. Both sides were then given a few weeks to reach an agreement on the terms of an order to quash the amendment, but failed to do so, and the case went back to court for a final hearing on 9 June.

The union always maintained the changes to the compensation scheme would have made it easier and cheaper to cut tens of thousands of civil service jobs and privatise more of our public services.

PCS deputy general secretary Hugh Lanning said: “We are delighted with the ruling that proves our members were right to oppose the cuts that the previous government tried to force through.

“It’s rare for a High Court judge to side with a trade union, so we believe this vindicates our stance and our assertion all along that this was a grossly unfair attempt by the government to rip up the rights of its own workforce.

“The new government now has a golden opportunity to show it is truly committed to consultation and negotiation, by getting round the table with us to agree a new scheme that is fair and protects the rights of civil and public servants.”

Richard Arthur, head of trade union law at Thompsons Solicitors, who acted for PCS, said: “The ruling confirms that a government cannot simply change redundancy rights which have already accrued for civil servants without agreement by the unions.

“With the exception of some favourable age-related changes, all the benefits in the new scheme are quashed and all the benefits in the old one are protected. The new scheme that was imposed on civil servants was simply unlawful.”

The ruling comes days before the coalition government is expected to announce further cuts in public spending in its emergency budget next Tuesday (22 June).

PCS will hold events across the country on Tuesday, including outside the Treasury in Parliament Street in London between 12pm and 1pm, and will launch its Tax Justice and Jobs report that details how more than £120 billion is estimated to be lost to the economy every year through tax being evaded, avoided and uncollected.