But while it's not unusual for whistleblowers to face problems, it is possible to raise and pursue concerns while keeping your own reputation intact and your job secure - if you go about it the right way.
Many people are unaware that whistleblowers can't legally be dismissed for their actions as long as they're reporting a criminal offence, failure to obey the law, miscarriage of justice, danger to someone's health and safety or damage to the environment. And they don't have to be employees to have this protection: the self-employed, agency workers and people who are in training with employers can also all be eligible.
However, in June this year, changes to the Public Interest Disclosure Act came into force which alter the conditions under which whistleblowers qualify for this protection. Now, it's necessary for whistleblowers to believe they were acting in the public interest. However, they're no longer required to be acting 'in good faith' - in other words, whistleblowers won't lose their protection from dismissal even if they're deemed to be motivated by the desire for personal gain or vengeance.
This is an important change, according to Simon Rice-Birchall, partner at Eversheds law firm, which carried out a survey into whistleblowing earlier this year. "Our study suggested that nearly one third of respondents have encountered some form of bullying or other detriment in this context," he says. Too often, says Rice-Birchall, "employees are simply too scared to voice their concerns, unaware or mistrusting of the legal protection offered."
So what are the most important points to remember when raising concerns about bad practice within your workplace?
Collect your evidence carefully
Be specific about what you think is wrong and stick to the facts; don't drag in every tiny grievance you might have, as this will almost certainly damage your case. Always remember, too, that you may be wrong about your suspicions or misinformed - be wary of going in with all guns blazing unless you're absolutely certain about your facts. Keep copies of any relevant information you have in writing, and take notes on conversations.
Work with others
You may not be the only person with concerns about your organisation, and raising these as a group can be more persuasive, as well as making you feel less vulnerable.
Follow organisational procedures
For most disclosures, Wikileaks really isn't the best place to start. First, check whether your employer has a whistleblowing policy, and, if so use it to make your report - if you feel you can. If you genuinely believe, though, that your employer will cover up the issue (or has already done so), or if you believe you'll be treated unfairly if you complain, you can instead make a report to a lawyer, a government minister, or one of a list of prescribed bodies available from the Department for Business Innovation and Skills.
Don't break the law yourself
Staff aren't protected from dismissal if they break the law when making a disclosure, for example by breaking the Official Secrets Act. Nor are they protected if they received their information while giving legal advice; this is known as legal professional privilege.
Think carefully about going to the media
You're a lot more likely to get favourable treatment if you've reported concerns to your employer or a prescribed body than if you rush straight to the tabloids. On the upside, you'll have a good chance of remaining anonymous - and even of getting paid - but on the downside, you won't receive protection from unfair dismissal unless it's a particularly serious case or you didn't get a reasonable response elsewhere. And remaining anonymous isn't necessarily a good thing, as it may make it harder for the authorities to investigate your allegations.
It's easy to get the impression that whistleblowing inevitably backfires, but that is by no means the case. A survey carried out in June by YouGov for whistleblowing charity Public Concern at Work found that one in ten workers had had a concern about possible corruption, danger or serious malpractice at work - but that most had safely been able to raise it with their employer. As chief executive Cathy James says: "It is startling that so many workers have witnessed serious wrongdoing in British workplaces, but reassuring that workers are willing to raise the alarm."