A union has called for talks to be reopened as it seeks an additional pay award for teachers next year.

The National Association of Schoolmasters Union of Women Teachers (NASUWT) has written to education secretary Angela Constance and the Scottish Negotiating Committee for Teachers (SNCT) to set out its case for further negotiations.

A two-year deal on pay and conditions was formally agreed by the SNCT in October last year, giving teachers a 1.5% backdated increase for the 2015-16 year and a further 1% in 2016-17.

NASUWT rejected the deal but was defeated by a majority vote to accept the offer.

The union has given several reasons for an additional pay award to be made in April 2016, including a lack of compensation for teachers for a "real-terms loss in salary of nearly 15% since 2010" and the ending of "career pathways", which helped classroom teachers progress to higher standards.

NASUWT has also cited an increase in inflation since the implementation of the two-year deal and a rise in national insurance contributions from April 2016 onwards.

The union also claims pay for teachers starting the profession has fallen "well behind that of comparable graduate professions".

Chris Keates, NASUWT general secretary, said: "Teachers have continued to deliver higher standards and have endured increased workload.

"It is now high time for negotiations to be reopened on an appropriate rewards system for teachers who have given, and continue to give, so much to the children and young people in their care.

"Investment in teachers is an investment in children's education."