Can a tutor help your child to make the grade?

Costing some £10,000 a year – £20,000 for a border – a private education for their children is beyond most parents' means. But it is much more affordable to arrange private lessons to complement a child's state schooling.

"Nothing beats one-to-one tuition for boosting a child's performance," says Susan Fieldman, regional editor of The Good Schools Guide. "State schools have 30 or more in a class and even private ones have 15."

Demand is greatest for GCSE and A-level tutoring but the biggest area of growth is in the primary sector, especially among parents who are hoping to get their children into a grammar school.

The most popular subject at all levels is maths, followed by English, with parents typically hiring a tutor for a couple of terms prior to an important exam. Anita Moss, founder of the Bright Tutors agency, says: "It's better to go for one hour a week spread across a year than cram, cram, cram." A realistic aim is to go one grade better than the predicted mark based on mocks.

Surprisingly, private tuition is an unregulated industry; anyone can set up as one. So parents have to be careful. "Insist that tutors are qualified teachers or that they have a degree in the subject they're tutoring together with some teaching experience," says Mylène Curtis, managing director of the Fleet Tutors agency. This means asking for copies of qualifications.

Ms Curtis adds that personal recommendation, either about an individual tutor or agency, is a good place to start. Going through an agency should also offer the reassurance that the people on their books are both qualified and do not have a criminal record.

Fees vary from £15 to £60 an hour, and some agencies charge an introduction fee – sometimes as much as £150. Booking a block of lessons is usually cheaper, though to ensure your child gets on with the tutor, it is a good idea to ask for a trial lesson before forking out for 10. Another way of cutting costs is to hire a tutor for two or more children at the same level. Fleet Tutors charges £30 an hour on average, but for a group lesson, it asks £8 per extra child.

Online tuition services, many based in India, can also offer big savings. The teachers on First Tutors' books charge £16.50 an hour at primary level, rising to £21 for A-level tuition. But you are then responsible for vetting the tutor yourself and, while they may be useful for specific questions, there are other potential disadvantages with online tuition generally. "Often they're not geared up to a particular syllabus or exam," says Ms Fieldman.

Also of dubious benefit is booking a tutor for an hour's quick fix before an exam. "And don't be duped into getting lessons for under-fives," stresses Ms Fieldman. "It's too much for them to cope with.