An investigation into the role of the 15,000 classroom assistants currently at work in Scotland's schools yesterday concluded that they are underpaid and often overworked.

An investigation into the role of the 15,000 classroom assistants currently at work in Scotland's schools yesterday concluded that they are underpaid and often overworked.

The number of classroom assistants has trebled since they were introduced in 1998 and they now play an integral role in supporting teachers across most primaries and secondaries.

However, a report by the Equal Opportunities Commission Scotland (EOC), to be published today, has found that some classroom assistants are earning as little as £5.68 an hour. That makes them among the lowest-paid local government workers in Scotland.

Because 98% of classroom assistants are female and the job is linked to caring for children, the EOC believes the workforce is an example of a wider problem of the pay gap between men and women.

Officials yesterday called for an urgent national action plan to address the undervaluing of a "vital" female workforce.

The report's recommendations include the creation of a national action group led by local authorities, the Scottish Executive and trade unions to address the imbalance.

EOC Scotland also wants the development of a national framework which would set out the role of classroom assistants and provide proper recognition of their work.

Rowena Arshad, EOC Scotland commissioner, said: "It's now time to put right the scandalously low pay that our classroom assistants receive for doing such a challenging and vital job in our schools.

"That Scotland's classroom assistants can take home as little as £500 a month in their pay packet amounts to a national disgrace."

Doris Littlejohn, investigation chairwoman, added: "We want to see an education system in which the role each classroom assistant plays is rewarded equally and fairly."

However, Pat Watters, president of Cosla, which represents local authorities, said the report was "over the top".

He said: "It was no surprise to councils that the report showed the valuable role they play and, of course, classroom assistants have a right to equal pay. Scottish councils recognise this and are using agreed methods of measuring jobs to ensure it happens."

The report found that hourly rates of pay for classroom assistants vary between £5.68 and £7.58 an hour with annual salaries ranging between £7000 and £10,000.

However, 97% of the 934 teachers surveyed felt that pupils are benefiting from the employment of classroom assistants mainly because pupils receive more individual help and support.

Meanwhile, Dr Brian Lang, principal of St Andrews University, called yesterday on the Scottish Executive to consider a graduate tax to help fund higher education.

The National Union of Students Scotland, however, is opposed to the graduate tax.

Its president James Alexander said: "Graduates that have financially benefited from their course already pay higher tax because they have increased earnings. There are also a large number of students who never benefit financially from their degrees, such as student nurses and those entering the voluntary sector."

An executive spokeswoman said Education Secretary Fiona Hyslop was examining student finance, but there were no plans for a graduate tax.

The proposal came as the Scottish Executive revealed fewer schoolchildren are drinking and smoking than two years ago.