Patrick Elias QC, for Wandsworth, told the court: 'The union is challenging the policy of an elected government by the use of sanctions by seeking to resolve in the industrial sphere that which should be resolved in the constitutional sphere.'
The union's members have voted to boycott all national curriculum assessment and testing. This summer's tests for 14-year-olds will be worst affected.
Wandsworth contests the union view that the dispute is a protest over the workload imposed by testing and therefore lawful under the Trade Union and Labour Relations (Consolidation) Act 1992.
Mr Elias said he was not suggesting that the union's position was a sham and that workload had been put forward to drum up a dispute. Workload was a strand, but the dispute was wider than that: it concerned the content of the national curriculum and the nature of testing.
Jeffrey Burke QC, for the union, argued that this was 'an old-fashioned trade dispute' about workload which had come to a head as a result of the increasing demands of the national curriculum and testing.
'There is an everlastingly accumulating increase in assessments and tests at each stage, year by year, subject by subject,' he said.
The case continues today when judgment will be given.
Inside Parliament, page 4