In an employment environment where very few of us enjoy absolute job security, there's much to be said for appending another substantial paragraph or two to our CV. Add to that the sharply increasing number of people coming out of universities with first degrees, and it's easy to see why there's a healthy market in postgraduate business-related courses.

But it's not just recent graduates opting to enhance their qualifications in this way. There's a widespread trend for mid-career workers to put in some solid study time to try to enhance their prospects in a rapidly changing world. In some cases, this is to make a sharp career change, to move into a job sector with better long-term prospects. And in other cases, this can be provoked by the most unanswerable catalyst of all: redundancy.

Among these mid-career movers, there are two distinct categories: those acquiring postgraduate qualifications tailored to a specific professional sector – often run by the relevant professional institution – and those taking a more general management course, which offers the potential to move higher up the management ladder in any number of roles. The most common postgraduate vehicle here is the MBA.

Career change is one of the most common reasons given to us when we do research into why people choose to do an MBA, says Jeanette Purcell, the chief executive of the Association of MBAs (Amba).

But she counsels against the assumption that an MBA can bring about a wholesale change of career. Don't try to change too much in one move, she warns. "To change location, job role and job sector all at the same time, particularly in the current climate, is probably asking too much of yourself."

At Kingston University, the one-year full-time MBA, which has been going since the Eighties, attracts numerous career changers and is in rude health. A total of 25 students – all with substantial management experience under their belts already – made up the course's February intake this year, following in the footsteps of a similar-sized cohort that started last September.

"Many of these have been made redundant in the last year or so," says Chris Bristow, manager of all Kingston's postgraduate business programmes.

"They've received a redundancy package, and are using it to invest in their future by doing a full-time course. They're taking a complete year out and hope to ride the bow wave of the economic recovery when they come back into the job market."

Someone in just that position, at City University's Cass Business School on the outskirts of London's financial district, is Andrew King, who began an MBA last September, having lost his job, in property fund management, at the end of December 2008.

An economics and Spanish graduate, coming out of Leeds University in 2003, King chose to do the MBA to widen his financial and management skills, with the aim of moving into a corporate finance role in an industry unrelated to the property market. So far, studying alongside engineers, people with creative backgrounds, former bankers and property professionals, he's found the programme just what he needs.

"It's definitely given me a more sophisticated and polished understanding of corporate finance, and I know more about how to use financial instruments," he says. "I've also got more formal marketing training, and been able to look at things like organisational behaviour in other sectors, which I've found fantastic."

This observation touches on the importance of researching the exact flavour and content of each MBA course before signing up. On this subject, Purcell's advice is to start from a clear understanding of what you want a business course to provide for you, and then to look for a business school that offers it in a course.

"It is so important to be absolutely clear what you want an MBA for," she says. "Only once you've made that decision will you have a good chance of finding the right MBA for you."

But while choosing the MBA route allows some flexibility in future job hunting, some career changers prefer to take a course with a specific new role in mind.

This was the motivation of Jeremy Chapman, 35, who landed his current role as a senior financial manager at the Olympic Delivery Authority (ODA), the body currently building facilities and infrastructure for the London 2012 Olympic and Paralympic Games, thanks to a postgraduate course he set out on a couple of years ago.

The course in question was a postgraduate certificate in management accountancy, run by the Chartered Institute of Management Accountants (Cima). Studying part time, Chapman took more than three years to complete the course, a journey started when he was working as a business planning manager for Transport for London (TfL), a job he moved into having begun his working life as regional manager for the Post Office.

"At the Post Office, I had nothing to do with numbers," he recalls. "At TfL, I started to get involved in budgeting, but realised that I needed to bolster my CV and get a professional qualification if I was to make progress in my career."

Chapman, now a chartered management accountant, attended weekly evening classes and had to complete assignments at home.

"The course was a slog, but it definitely paid off. It significantly affected my salary and standing at work, and helped me move into the ODA job. I now know I have the qualification to back up my day-to-day role."

Another professional body which provides postgraduate courses attractive to career changers is the Chartered Institute of Marketing (CIM).

Liz Ratcliffe, 38, was working in a relatively junior role in the marketing department of the Ordnance Survey when she decided to embark on the CIM's professional postgraduate diploma in marketing. This entailed six intensive residential weekends at the CIM's headquarters in Cookham, near Maidenhead, as well as substantial study and assignments completed at home.

"I decided I wanted to skill-up in an area," she remembers. And it paid off. As well as collecting a number of CIM prizes for the quality of her work on the course, she has now moved into a far more senior role, as head of product marketing and propositions, at the Ordnance Survey.

"It was very intensive and hard work over six months, but it has definitely been worth it. I now use what I learnt day in day out, and I am now working at a much more strategic marketing level," she says.

A similar path has been travelled by Victoria Perkins, 33, now marketing manager for dental products at the technology firm 3M.

A management science graduate, she joined 3M from university in 2000, first moving into a sales representative role. But she saw that acquiring the CIM qualification would enable her to move into a more senior position. So, over a few years in the middle of the past decade, she worked through the professional postgraduate diploma course.

"Without the qualification, I wouldn't have got the respect I now have at work," she says. "More than anything, it boosts your confidence when you stand up and make presentations at work.

"And I now use the letters after my name because I'm proud of them."