The home secretary’s imposition of a temporary cap on the number of skilled workers allowed into the UK from outside the European Union was ‘unlawful’ and must be annulled, the High Court has ruled.

Lord Justice Sullivan and Mr Justice Burton, giving judgment last Friday, said home secretary Teresa May had not gone through the proper parliamentary procedures when she implemented the cap last summer. They said: ‘There can be no doubt that she was attempting to sidestep provisions for parliamentary scrutiny set up under provisions in the 1971 Immigration Act and her attempt was for that reason unlawful.’

The cap, which is no longer enforceable as a result of the ruling, was a first step towards meeting the coalition government’s election commitment to reduce net migration from nearly 200,000 people per year, to tens of thousands. Ministers may reintroduce another cap in January when parliament returns from the Christmas recess. However, the new cap could also be challenged if ministers again fail to follow the correct procedures, including allowing parliament to vote on it.

The government is seeking permission to appeal the decision. Immigration minister Damian Green said: ‘We will do all in our power to continue to prevent a rush of applications before our more permanent measures are in place.’

The ruling followed a judicial review of the interim cap’s legality, brought by the Joint Council for the Welfare of Immigrants (JCWI) and the English Community Care Association.

JCWI chief executive Habib Rahman said: ‘This is a victory for democracy and the rule of law. It shows that the home secretary cannot simply sideline parliament.’