Teachers who work as private tutors are being urged to take out insurance to protect them from being sued by "litigious parents" whose children fail exams.
Concerns have been raised that tutors are not properly safeguarded from parents who could seek compensation for low exam grades or breaches of health and safety rules.
Teaching unions and legal experts are warning tutors, many of whom also work as state school teachers, that they are not immune to the growth of a "compensation culture".
Martin Pilkington, head lawyer at the Association of Teachers and Lecturers, said: "It is important teachers doing private tuition make sure they are properly covered. With the best will in the world, something could go wrong.
"We advise members to protect themselves against increasingly litigious parents and the expansion of the compensation culture."
The union said that its experience with private schools showed that some parents who pay for education can be particularly demanding if their children fail to achieve high grades.
Insurance would protect tutors from legal claims for negligence following disappointing test results, and health and safety claims if a child is injured.
There are concerns that cases launched in the United States could be repeated in the UK.
Christine Blower, acting general secretary of the NUT, said that union membership would cover private tutors in some cases, such as false accusations, but not all.
Four of the teaching unions have now struck a deal with a broker for cut-price insurance in a bid to encourage teachers to sign up.
Richard Hartley, from the Alan Boswell Group brokers, said: "Today's no-win, no-fee contracts with lawyers mean individuals do not hesitate to pursue a claim if they feel there may have been some form of negligence."
Teachers working in schools are automatically covered against such claims, but many do not realise the need for similar cover when working privately.
Owen Flatley, a qualified languages teacher who has been a private tutor for the past two years, said the risk of being sued was worrying and that he was considering taking out insurance.
"It's a pretty sad state of affairs that parents are getting irate if their children fail exams," he said. "It's not just a tutor who is contributing to their education.
"Most of the time, parents are happy as long as their children are being motivated and getting the most out of the lessons. But you have to make sure you don't leave yourself open to allegations."
The private tutoring industry is largely unregulated, but academics at London University's Institute of Education have been assessing how it operates. They are due to present their findings to the Department for Children, Schools and Families shortly. An institute study from 2005 suggested that more than one in four state school pupils had received private tuition.
As previously revealed in The TES, state schools and local authorities have also paid thousands of pounds to send selected pupils, typically on the CD borderline, to private tutors and crammer schools to help boost league table rankings.
A separate survey last year suggested that half of children at grammar schools had been taught by private tutors to help them prepare for the 11-plus.