Independent schools in Scotland generate the same amount of money and jobs as the energy and food industries, according to the first nationwide report on the economic benefits of the sector.
The study commissioned by the Scottish Council of Independent Schools (SCIS) found that in 2013 its members contributed nearly pound;292 million to the country's economy, pound;4 million more than the nation's fishing businesses.
Private schools in Scotland also employ more than 7,500 people directly, roughly equivalent to the workforce of the oil and gas industry north of the border.
Taking indirect economic impacts into account, such as expenditure on school uniforms, supplies and building new sports facilities, the total financial contribution of SCIS members in 2013 was pound;445.8 million, according to the report - greater than the economic benefits generated by some of Scotland's leading universities.
SCIS said it had published the study to spell out how vital the private sector was, as concern grew over the impact of an "unprecedented level of political activity" in the next few years in the UK, including the forthcoming referendum on Scottish independence.
SCIS director John Edward said: "It is an appropriate moment to provide an insight into, and supporting data on, the role of the sector in Scotland that moves away from narrowly focused and policy-light arguments based on outdated preconceptions of the diversity and profile of the sector and the people within it.
"Distracting and intrusive debates about the educational background of political and other public figures make for lively politics and good copy, but fail to recognise that most independent school pupils and staff live in and around their local communities."
Referring to ongoing controversy about whether private schools should be allowed to operate as charities, he added: "It is a striking characteristic of the debate on charitable status, and widening of access through means-tested bursaries, that old and unrevised assumptions about the socio-economic background of pupils remain."
The SCIS represents more than 70 independent schools across the country, which together educate about 32,000 pupils. The report equates the impact of the sector to that of some of the largest councils in the country.
The authors found that the number of full-time teachers employed by SCIS schools was 3,459, or about 6.4 per cent of the teaching workforce in Scotland, making the independent sector equivalent in size as an employer to the sixth biggest of the nation's 32 local authorities. Independent schools also provided an education for 31,146 of the 702,576 pupils across Scotland in 2013, or 4.5 per cent, equivalent to the number of students educated at state schools in the seventh largest council region in Scotland.
School Leaders Scotland (SLS), which represents both state and fee-paying schools, said the private sector should not feel the need to defend itself. SLS general secretary Ken Cunningham said: "It's probably a sign of the times with the independence debate.but they are part of the fabric of society.
"What would be the point in a similar report for state schools? I think the point here is to suggest to people who are concerned about the existence of independent schools that actually they contribute a significant amount to the nation's economy."
Last month SCIS warned that parents from overseas could be deterred from sending their children to Scottish independent schools because of the UK government's "unwelcoming" immigration policy. The SCIS report comes just weeks after a similar publication produced by the Independent Schools Council found that fee-paying schools contributed pound;9.5 billion annually to the UK economy, supporting 227,000 jobs and generating pound;3.6 billion in tax revenues.
But a spokesman for local authorities body Cosla said that local government and private schools worked on different scales, making comparisons unfair. "State comprehensive education is a central driver of the Scottish economy and has been a central pillar of Scottish society for decades," he said.
"Local government values the role played by the independent sector at providing care and education for children with additional support needs, but the fact that the SCIS have the capacity to produce a report like this demonstrates the difference in scale between the two sectors.
"Local government's focus remains on ensuring that all children in Scotland get the best possible education and have the skills that will prepare them for the future."