Campaigners bidding to ban schools from teaching creationism in science lessons are "militant atheists" who want to impose their own views on youngsters and discourage questioning, a church leader has claimed.

Reverend David Robertson, who will become the next ­Moderator of the Free Church of Scotland in May, accused the ­Scottish Secular Society (SSS) of using ­the issue of creationism in schools to "undermine and attack Christianity in pursuit of their sectarian and bigoted anti-religious beliefs".

The SSS has put forward a ­petition calling on Education Secretary Mike Russell to issue guidance to publicly funded schools and colleges to "prevent the teaching of creationism and related doctrines as viable alternatives to established science".

Creationism is the belief that the universe and living beings originate "from specific acts of divine creation", with the SSS saying last year that teaching of this "and the denial of evolution has been found in three separate Scottish schools in a very short period of time".

This, it argued, raises concerns that "such views and excesses may be endemic in the system".

The SSS - whose proposal would allow creationism to be discussed in religious education classes - will make its case to MSPs at the Scottish Parliament's Public Petitions Committee next week.

Ahead of that, Rev Robertson claimed the group was seeking to "impose an atheistic philosophy on children".

The Dundee-based preacher said: "Since when was science ­determined by MSPs? Once we have politicians telling science teachers what to teach, on the advice of one particular faith belief, then we are in real trouble.

"Could we not have a more tolerant and Christian view of science? And could we not ­encourage children to think about the issues for themselves, rather than just tell them what to think?"

The St Peter's Free Church minister continued: "The ­secularist faith tells them that there can be no intelligent design, because of course they do not want to believe even in the possibility of a designer.

"However in this they are not being scientific - they are just seeking to impose their religious view upon the whole of society."

"It is desperately disappointing that secularists believe the key danger in 21st-century Scotland is apparently creationism, not the 20 per cent of Scottish children who live in poverty, nor the many thousands who have faced the ravages of sexual abuse and drug addiction."

Both SSS chairman Spencer Fildes and Professor Paul ­Braterman, the group's scientific adviser, are due to appear before the committee on Tuesday.

In a submission to MSPs, Mr Fildes argued that nothing in the petition would prevent the discussion of creationism in its "proper place as part of the study of ideas". He also claimed that it did not "infringe on individual freedom of belief".

The SSS said at the moment, the Scottish curriculum does not specifically make clear that "teaching creationism as an ­alternative to the overwhelming scientific consensus on the origins of the universe, or in any context as a viable alternative to accepted science, is unacceptable".

But it stated: "This is not the case in England and Wales, where the Department for Education has stated that 'We do not expect creationism, intelligent design and similar ideas to be taught as valid scientific theories in any state-funded school'."