Gordon Brown has warned of a dangerous year ahead for the economy. If the same could be said for your finances, maybe it’s time to consider taking a second job.

About one fifth of teachers moonlight in jobs from tutoring and exam marking to waitressing and even wedding photography. But don’t staff who juggle two jobs face the threat of burnout? And what happens if the head stumbles across you juggling cocktails or serving chicken dinners on the sly?

At the last count, 84,000 teachers were earning a second income, according to the Office for National Statistics, and given the popularity of cash-in-hand work such as tutoring, the actual number is likely to be even higher.

With teacher salaries starting from pound;20,000 outside London and 40 per cent of graduates leaving training with more than pound;10,000 of debt, according to the Association of Teachers and Lecturers, it’s no surprise that many are looking for an emergency supply of cash.

But, seeing as the average classroom teacher works 50 hours a week or more, including reams of marking at evenings and weekends, how do these superhuman specimens squeeze the extra work in?

Adam Gale, a 41-year-old NQT from Hampshire, thinks it’s all about finding the right post. Not only does his Saturday job at a local library in Gosport top up his pound;19,000-a-year teaching salary nicely, but it’s actually improved his lesson planning, he tells The TES Magazine.

“It’s absolutely perfect. I’ve got access to every book in the catalogue as well as the local studies centre, both excellent resources. And when there’s spare time, my managers are happy for me to plan my lessons on the internet. It’s been such a bonus.”

Obviously plum jobs are hard to come by, and teachers should think long and hard before taking up potentially gruelling work such as waitressing or shelf stacking.

While some staff enjoy the buzz of life in a busy industry, a flexible job that lets you choose your hours and decline work when you’re drowning in marking can be a better proposition.

Babysitting has proved the ideal way for Kelly Glass, a 30-year-old middle school teacher from Bedfordshire, to clear the debts she’d built up as a mature student. She accepts regular work from babysitting agency sitters.com, which pays her pound;5.50 an hour on top of her pound;20,133 salary to do an evening a week.

The vetting process, which includes inevitable hurdles such as an extra CRB check, is demanding. But the extra income has been a lifeline for the new teacher. “Everyone’s been lovely and I’ve never had a horrible child or parent,” she says. “The children are usually in bed within half an hour of you walking in the door so I take my assignments with me.” Babysitting isn’t the only job where your childcare experience will put you at the top of agency lists. Nannying in the holidays pays about pound;200 a week, but beware, struggling with screaming tots when you have just escaped the classroom isn’t everyone’s cup of tea.

Moonlighting teachers should also be aware that their boss might take a dislike to their extra job, if it starts affecting their main one.

“Most teachers’ contracts won’t explicitly say they shouldn’t have a second job,” says Mark Blois, a partner at Browne Jacobson, a law firm. “But it could be seen as a breach of the implied terms of trust and good faith that are present in any contract, which assume both parties will be honest with each other. Best practice is to be open with your employer and try and come to an agreement.

“If you were tired from working in a bar and something happened to a child in your care, liability could come back to you, especially if you had been working secretly.”

In reality, most heads are happy to turn a blind eye to second jobs, providing they don’t bring the profession into disrepute. So don’t make a career choice that wouldn’t sit well with the PTA, like the primary teacher who was struck off the teaching register for three years in 2005 after officials realised he was doubling as a prostitute’s driver.

But as Megan Guinan, 41, a maths teacher from Epsom who spends three hours a week book keeping for a local company, puts it: “It’s not really any of the school’s business what I do out of hours.”

Her pound;5,000-a-year job not only hones her maths skills, but paid for a two-week safari in her native South Africa last year. It’s an enjoyable way of supplementing her pound;24,000 part-time teaching income. “And it’s great to come from the chaos of the classroom, to somewhere very calm and controlled,” she says.

Megan found the job through a friend, and this can be a useful way of tracking down extra work. Ask fellow teachers how they save up for treats and holidays (you’ll be surprised how many are moonlighting) and let your friends outside the classroom know you are on the lookout for work.

And finally, remember to consider all the possibilities. If you’re a French teacher with a bigger nose for le mot juste than Gerard Depardieu, remember freelance translators are always in demand. An English teacher with a little stash of rare books? Sell them on eBay. And if you’ve always had a passion for acting, why not sign up with an extras agency?

Alice Matthews, 41, a special needs teacher from Falkirk in Scotland, won goods equivalent to pound;4,000 last year from her quirky second job: entering competitions in magazines and online.

“I won an HMV gift card, shoes, books, a holiday in the New Forest, pound;200 in cash and five short breaks last year,” she says. “It’s lovely to come home from a hard day’s work and find something nice in the post.”

What can I do?

Tutoring

This is the old faithful. Sign up with an agency or advertise on sites such as www.hometutorsdirectory.co.uk or www.firsttutors.co.uk and take the whole fee yourself. Flexible hours and earnings of up to pound;20 an hour.

Babysitting

Make your classroom experience count. Online agencies www.sitters.co.uk and www.topnotchnannies.com are favourites with teachers. Pay from pound;5-10 an hour and you can mark while you earn.

Extras work

No acting experience is necessary to make like Ricky Gervais. But you’ll need to pay up to pound;100 to join an agency. Try www.castingcollective.co.uk or www.nasaa.org.uk to find a company in your area. You can expect up to pound;100 for a day’s work. But be careful to choose a reputable agency.

Bar work and waitressing

Tiring but sociable. Ask about shifts at your local pub, cocktail bar or restaurant. Or why not contact luxury party-throwers www.admirable-crichton.co.uk who hire staff to wait at showbiz bashes? Rates vary.

Door-to-door

Sparky types are in demand at www.partylite.co.uk, who sell fragrant candles and www.avon.uk.com, make-up specialists, to meet clients at their home and introduce the brand. The hours are flexible but so is the salary (Avon pays pound;1 for every pound;4 you sell).