The government's 'unilateralist' approach to interpreting the justice provisions of the Lisbon Treaty has come under fire from a parliamentary committee.

In a report published this week, the House of Lords EU Committee condemns as 'legally unsustainable' the government's interpretation of the protocol under which it opts into EU justice and home affairs measures. 

An opt-out of justice measures was negotiated by the Labour government in the run-up to the Lisbon Treaty, which came into force in December 2009. On that date, the EU’s competence to propose legislation covering asylum, immigration, civil and criminal justice and police cooperation was consolidated under one ‘title’, known as Title V.

The UK (and Ireland) are excluded from participation in legislation proposed or adopted pursuant to Title V, unless they decided to opt into it.

The Lords committee set up its inquiry after receiving letters from the home secretary and justice secretary last last summer. 'We wanted to understand the government’s position and its implications,' its Labour chair, Baroness Quin, said. 

'What we have discovered has astonished us,' she said.

'From the outset we struggled to find any witnesses who supported the government’s position. The weight of the evidence left us in no doubt of three things: that the government’s interpretation of the opt-in protocol was legally unsustainable; that its litigation strategy ignored the case law of the court; and that its stance could run counter to the UK’s own interests as well as undermine its good standing among other member states.

She said that the government’s 'broad interpretation' of the opt-in provisions would give the EU itself wide powers to increase its competence in other areas – 'a consequence this government certainly does not want'.

The committee recommends that the next government 'abandon what amounts to an unjustified policy of unilateralism that has brought no tangible benefit to the UK'.