Exams for which pupils are expected to believe that the Loch Ness monster disproves evolution have been deemed equivalent to international A-levels by a UK government agency.

The National Recognition Information Centre (Naric) in Cheltenham, which advises universities and employers on the rigour of lesser-known qualifications, has ruled that the International Certificate of Christian Education (ICCE) is comparable to courses such as international A-levels, the Times Education Supplement has found.

Teenagers studying for the certificate, which is taught in about 50 private Christian schools in the UK, spend half their time learning from evangelical US textbooks. The curriculum is based on the Accelerated Christian Education (ACE) programme, which describes its ideology as "Christian fundamentalist".

Jonny Scaramanga, who was a pupil at a school in Bath that used the textbooks, has complained to Naric that the books tell pupils that the Loch Ness monster "appears to be a plesiosaur" and helps to disprove evolution.

The textbooks also state that apartheid helped South Africa because segregated schools "made it possible for each group to maintain and pass on their culture and heritage to their children".

One of the textbooks tells pupils: "Have you heard of the 'Loch Ness Monster' in Scotland? 'Nessie,' for short has been recorded on sonar from a small submarine, described by eyewitnesses, and photographed by others. Nessie appears to be a plesiosaur.

"Could a fish have developed into a dinosaur? As astonishing as it may seem, many evolutionists theorize that fish evolved into amphibians and amphibians into reptiles. This gradual change from fish to reptiles has no scientific basis. No transitional fossils have been or ever will be discovered because God created each type of fish, amphibian, and reptile as separate, unique animals. Any similarities that exist among them are due to the fact that one Master Craftsmen fashioned them all."

Naric, which is funded by the Department for Business, Innovation and Skills, has said the ICCE is equivalent to the advanced certificate of Cambridge International exam board's international A-levels.

Tim Buttress, Naric's spokesman, told the TES its remit did not cover the curriculum's content.