Since becoming education secretary in July last year, Nicky Morgan has been at pains to build bridges with the teaching profession. In contrast to the more abrasive approach associated with her predecessor Michael Gove, Ms Morgan's charm offensive ahead of May's general election has focused on addressing teachers' concerns about workload.
And although the Workload Challenge has not been without its critics, her more emollient approach has served to take the sting out of the Department for Education's relationship with teaching unions. Although the NUT and NASUWT unions' trade disputes with the government are still active, the most recent national action by the NUT took place in July 2014 - days before Mr Gove was removed from his post.
Now his successor has moved to bring a formal end to hostilities before the election. In a letter to the leaders of five teaching unions, Ms Morgan has called for all open industrial disputes to be resolved "as soon as possible".
"Four years have passed since all open trade disputes began and the educational landscape has changed significantly since they began," she writes.
"I therefore hope that those unions in dispute with me will consider resolving their disputes as soon as possible."
Ms Morgan's letter is addressed to the NUT, Voice, the ATL, the NAHT headteachers' union and the Association of School and College Leaders, and is a response to concerns raised by those five unions about the Workload Challenge. Of the five, only the NUT is in active dispute with the government.
Since the NUT and NASUWT announced their disputes in 2011, the former has held four days of national strike action, with the latter holding a series of regional strikes. Yet Ms Morgan's letter makes it clear that there is no room for manoeuvre. "The direction of policy on teachers' pay and pensions is set: it has not and will not change," she writes.
The message has been greeted with hostility by the unions. NUT assistant general secretary John Dixon told TES it would be "absolutely impossible" to resolve the dispute unless ministers were prepared to discuss the "substantive issues" of pay and pensions.
"We want to talk about possible resolutions, but you can't do that if you eliminate any talk about policy," he said.
"We need to address the attack on teachers' pay that has come about as a result of government policies. We still have all our concerns over the pensions proposals that are ensuring teachers are working longer for less and having to pay more in. And we need a proper dialogue on the causes of workload difficulties, which include government policies."
Chris Keates, general secretary of the NASUWT union, confirmed that the organisation's dispute was also still live. "No progress has been made on the substantive issues that are fundamental to our dispute and the secretary of state is fully aware of what these issues are," she said.
Russell Hobby, general secretary of the NAHT, criticised Ms Morgan's approach.
"I don't think you resolve trade disputes simply by asking the other party to close them down," he said. "I think you have to negotiate on the causes."
But Brian Lightman, general secretary of the ASCL, said it would be "in the best interests of our young people" for the dispute to be resolved.