The NASUWT says Jarvis should not be awarded the �44m contract because of its safety record.

The engineering company was responsible for railway maintenance at the site of the Potters Bar rail crash in 2002.

But Jarvis has responded by saying its operational safety record compared with the best in the country.

Five schools

Derby NASUWT secretary Dave Wilkinson said: "I think it would be political madness for any group on the council to hand over a significant chunk of Derby schools to Jarvis.

"It may potentially lead to industrial action if things start to go wrong straight away and it would lead to disruption of children's education.

"So I would hope the council would listen to what the NASUWT are saying."

Three companies are bidding for the contract to build five schools in the Derby area.