The move comes after last week's Court of Appeal ruling against the south London borough that a teachers' boycott of the tests was part of a legitimate dispute over excessive workloads. A letter from Donald Naismith, director of education, to the heads of the borough's four secondary schools offers 'support with the supervision and marking' of tests.
'To abandon all efforts to provide information about pupil progress this year would be to set back the whole programme two years for some pupils,' the letter says.
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said his members would not stand in the way of the move. 'Effectively, they are bringing in people to help with the workload of the tests, which is what we wanted all along.
'Of course, the results of such tests would be extremely suspect and of little value to anyone because some pupils will not have been prepared properly due to the boycott,' he said.
The council said the test results, would not be used for league tables, but would still be useful despite the boycott of the preparation by some teachers. 'The offer is on the basis that the council will get the information back for internal use.' Teams of staff would be provided by the education authority from a supply pool.
The Department for Education said: 'We welcome Wandsworth's action, which is in the interests of the children and of raising standards.' But Ann Taylor, Labour's education spokeswoman, called Wandsworth's action 'incredibly confrontational'.
Mr de Gruchy issued an angry statement last night saying he had been informed that the Government was poised to rush through legislation making it illegal for teachers to carry out their threatened test boycott.
The move - which was strongly denied immediately - would be in line with the contents of a leaked letter allegedly written by Gillian Shephard, the Secretary of State for Education, to Mr Patten.
She allegedly wrote: 'I have been considering a possible amendment to the law to make it clear . . . that industrial action is unlawful if . . . it is clearly designed to frustrate the carrying out of a specific statutory duty.'
Letters, page 27