The 1980 Education (Scotland) Act and the Standards in Scotland's Schools Act 2000 place a duty on local authorities to educate excluded pupils. The Scottish Executive's own guidelines on exclusions state this duty "arises immediately and must be discharged without undue delay".
But data provided by the Executive last week revealed that schools in Dundee, Angus, Clackmannanshire, East Renfrewshire, Falkirk, Moray, Orkney, Perth and Kinross, Shetland, South Ayrshire, Stirling and West Dunbartonshire have made little or no alternative provision.
One of the best-performing authorities, Fife, made provision on only 36 per cent of occasions.
Exclusions in Scotland are mainly temporary. In the year 2003-04, half of these lasted four to 10 days, and 5 per cent (1,958 cases) were of two weeks or more.
In only 8 per cent of a total of 38,743 temporary exclusions was some form of education provided, the figures reveal.
A new report on exclusions due out later this month is expected to show a slight rise (0.97 per cent) in temporary exclusions, adding to a 7 per cent increase in the previous year, following the removal, in 2003, of government targets designed to cut exclusions.
The Scottish Parent Teacher Council says it is being contacted by parents who are often at work so their children are being left home alone or are on the streets. "They are getting no education at all and that is not going to solve anything," Judith Gillespie, its development manager, says.
Kathleen Marshall, Scotland's Commissioner for Children and Young People, points out that they have a right to education, both under international and Scottish law. "That right remains even when they have been excluded from school," she added.
Since a third of these pupils have been excluded on more than one occasion, Professor Marshall warned: "The cumulative effect of deprivation of education on these pupils could be significant."
Executive guidance insists schools send work to pupils' homes immediately.
But George Haggarty, president of the Headteachers' Association of Scotland, said this was difficult to deliver. He said: "Schools are not funded to provide a staffing element for this. And these children will only do work if they are under the supervision of teachers."
The Executive does give schools a maximum of 10 days to implement its guidance. But Iain Nisbet, head of Govan Law Centre's education law unit, noted that headteachers have interpreted this to mean they need do nothing in the first 10 days.
Mr Nisbet added: "This is not only unlawful - it is counterproductive.
These children are already not engaging properly in school work. The position will be even worse when they return from a period of exclusion."
The Executive has, since 1999, given local authorities more than pound;104 million to fund measures designed to improve discipline and find alternatives to exclusion.
But Lindsay Roy, immediate past president of the secondary heads'
association, said that, although there were several initiatives to prevent exclusions, "we are not aware of any funding coming to schools to support youngsters while they are excluded".
David Eaglesham, general secretary of the Scottish Secondary Teachers'
Association, took an uncompromising view.
"Regardless of what lawyers say, unruly pupils have forfeited their right to education. Like disruptive passengers on an airline, they have to be dumped. Exclusion is a penalty sanction. We need to be hard-nosed about the situation. Kids understand that," he said.