The conflict over the European working hours' directive is widely accepted in Westminster and Whitehall to be the most urgent between the British government and the EU. Ministers regard the success of their legal challenge as a crucial test of the 'subsidiarity' principle that member states should regulate their own affairs unless there is an overwhelming case for European intervention.
David Hunt, Secretary of State for Employment, will disclose today that government lawyers have entered a robust defence before the European Court of Britain's right to determine what, if any, legal restrictions on working hours should be imposed on industry.
In particular, the Government will challenge the EU's right to impose the directive under its health and safety regulations, which are passed under qualified majority voting. This system means that no single country has a veto. Instead, government lawyers will argue such legislation falls within the ambit of directives requiring unanimous support.
The timing of the move is not without risk. If the European Court were to rule against Britain, the judgment, unlikely to be made inside two years, could come in the run-up to a 1996 or 1997 election. If it came down in favour of the universal 48-hour maximum working week it would be a humiliating pre- election rebuff.
The decision to face down Brussels - and the timing of the move - is in line with the aggressive approach planned by even pro-European ministers, like Mr Hunt and Douglas Hurd, the Foreign Secretary, in the forthcoming elections campaign. Mr Hurd will attack the creeping centralisation of the EU in a keynote speech this week.
Britain has already served notice that it does not intend to implement the working hours directive - which the Government argues would sharply reduce the competitiveness of industry - until any legal challenge has been resolved.
Mr Hunt will say today that the directive - adopted in November 1993 - is not about health and safety, is a flagrant breach of Community rules and is part of a ploy to 'smuggle through the back door' parts of the Social Chapter - from which Britain has opted out.
Mr Hunt's submission will insist that Britain has an unrivalled record on genuine health and safety legislation and that to include the working hours directive under that category is 'irrelevant' to real concerns about health and safety.
The issue over the working hours directive, which has been strongly pressed by Germany in an effort to ensure other industrialised member states face similar social costs to its own, came to a head after the Government failed to persuade other countries to agree a compromise that would have allowed individual workers to have opted out of a maximum working week.