You’re not getting on with your mentor. Your teaching styles and personalities are different. You want to set a quiz, he wants to set an essay. He likes Pop Stars The Rivals, you prefer Fame Academy. He voted for Melinda Messenger to win Celebrity Big Brother, you backed Mark Owen.

Often such personality clashes will end only in low-level bitching with other students, or a few cross words in the staffroom after a busy week. However, the importance of the relationship with your mentor should not be underestimated.

When you start applying for jobs, prospective employers will probably want to see a reference from your mentor. A good reference will mean that interview invitations will come flooding in. A bad reference might leave you lagging behind your peers, as their careers take off.

So what can you do if you are worried about the reference that your mentor or tutor has given, or might give, about you? An obvious first step would be to come straight out with it, and ask your mentor to give you a copy. Many mentors and tutors regard it as good practice to show a reference to a student who asks to see it, and you may get to see yours without difficulty.

But what if your mentor refuses to give you a copy of your reference: can the law help? Data protection legislation allows people, in theory, to obtain the information about themselves held by an organisation or a person. Many people think that data protection laws only apply to computer systems, and until recently this was true. Now though, the legislation also applies to paper filing systems, including drawers in school offices full of job applications, or filing cabinets in your mentor’s office stuffed with references and lesson observations.

Asking for data held by an organisation is known as a “data subject access request”. To be legally effective, the request must be in writing. It could be for all or any information that a school holds about you. In practice it is better to set out the precise information that you require, in this case your reference.

The school can insist on charging a fee of up to pound;10 for access to data, but must comply with a request within 40 days of receiving this fee. If you do decide to make a data request, then it is probably best to include a pound;10 cheque in your letter, made out to the school, so that there is no excuse for delay.

Who should you make the request to? Do not ask your mentor or tutor, if they have already refused. There is an exemption within the law which a person giving a reference can rely on in refusing to give you a copy. However, there is also a loophole which can be used to get the reference through the back door. Contact the school that has received your reference, as the exemption does not cover the document once it is in the hands of the school to which you have applied. Act quickly, as you might find that your details have been destroyed after a candidate has been appointed.

So, now you’ve got hold of your reference - either amicably, after a request to your mentor, or with increasing irritation after contacting one of the schools to which you have applied. There’s a good chance that you will discover that your “bad” reference has been given by omission. A person reading a reference is just as likely to be looking for the things that have not been said as those that have, and a bland reference is often just as damning as one that highlights areas where “support is needed”, or criticises you explicitly.

If you disagree with your reference, how can you change it? Where a relationship between a student and their mentor or tutor is constructive, it might be that a reference can be changed by negotiation, especially if it is shown there is a risk of it being misread by interviewing panels. It might also be easier to persuade your mentor to change things that are factually wrong, rather than those things that reflect his or her opinion.

Thinking now about the quality of the relationship with your mentor will have more practical benefits than resorting to the law later on.

Speak to someone straight away; if not your mentor, then perhaps a college tutor or another teacher. The problem might be one that can be solved. If not, then it would be better to move school than to risk your teaching practice being bogged down by personality issues.

If you solve the personality clash early on, the problem of an unfair reference will not arise.

Ed Podesta, a former IT solicitor, is a PGCE student at Oxford