The pack, which was put together in Calderdale and distributed to schools, was withdrawn by Government Ministers who described it as "misguided and inappropriate".

Now councillors and teachers are demanding answers over how the teaching material, called Things Do Change, was developed and how much it has cost the taxpayer.

The Calderdale branch of the National Union of Teachers has called for an inquiry to find out who sanctioned the material before it was later withdrawn.

The issue was also added as an emergency item to last night's children and young people's scrutiny panel meeting at Calderdale Council.

Committee chairman Megan Swift has been contacted by relatives of a victim of the July 7 bombings in London who were said to be "deeply upset".

The NUT wants to know why Calderdale teachers and teaching unions were not consulted over the creation of the pack and how much it has cost.

Calderdale NUT branch secretary Sue McMahon said: "It is clear that the upset and damage that the material has caused was unnecessary.

"It is disturbing that the pack did not have any input from our profession during a considerable period of time. Without the full involvement and expertise of the teacher unions and teachers the resource was unlikely to be appropriate.

"I am deeply concerned that Calderdale Council has a golden opportunity to rectify the situation but again fails to consult, effectively freezing out teachers.

"The NUT has no option but to call for a full investigation as we have been sidestepped throughout the whole process. This pack should not be re-issued before the findings of the report are brought back to the scrutiny committee.

"We would expect this before the end of this term – nor should the pack be issued without the full involvement of teachers."

The pack was hastily withdrawn two weeks ago, causing embarrassment to the Government which had previously recommended it as a way for teachers to address issues surrounding violent extremism.

One module, which focuses specifically on the July 7 bombings and the impact on different communities in Britain, suggests students could "prepare a brief presentation on the 7/7 bombings from the perspective of the bombers".

It also suggests pupils could look at the attacks, which were carried out by four men with West Yorkshire links, from the perspective of Muslims in Britain, non-Muslim Asians in Britain and other Britons.

The pack, which includes a DVD and costs £200, had been welcomed by councils and more than 100 had been sold to schools.

Calderdale Council's head of housing and community support, Mark Thompson, said: "Things Do Change is a fully resourced training programme that aims to encourage tolerance and prevent violent extremism amongst young people.

"The training programme has been produced in close partnership with West Yorkshire Police, Calderdale Interfaith Council and other organisations committed to tackling the causes of extremism.

"The council and its partner agencies in Calderdale are convinced of the value of the training pack. We are however making one or two minor adjustments to the document to eliminate any possible cause for misinterpretation."