School trip day. Everyone’s smiling, everyone’s excited - except you. You’re stressed about the three children not there.

1 Make sure that when drafting your letter to parents that you lie blatantly about time of departure: about 30 minutes earlier should ensure that every one arrives on time.

Having counted the children three times already - just in case one has escaped between leaving the assembly hall and boarding the coach - it’s time for your speech about behaviour on the coach. “No shouting, no standing. Be kind and considerate to the driver...” and so on. Ask if there are any questions. There’s usually only one: “What time is lunch?”

2 When setting the agenda for the day, slot a meal in as early as possible to minimise the number of times you have to hear: “Can we have our lunch now?”

Packed lunch on school trips is a bit of a phenomenon: it’s the most important thing of the day - even for the children who have packed lunch daily.

It’s a big talking point among friends - what they’ve got and what they can swap - and, for some, it’s the only reason they go on school trips, regardless of how exciting you think the day might be.

3If you can, have enough adults on the trip to be able to split into groups of four. This will also be useful at lunchtime (in a local park) when adults follow a rota for the “five- minute loo break”.

Four is a good number. Five can be a handful, but with four you can get them into pairs. With infants, it needs to be one adult to two children.

4 Remember that some parents need as much looking after as the children Make sure you have parent volunteers who are a help, not a hindrance. They need to know exactly what their duties are, and what to do in an emergency.

If you do find yourself in the unfortunate situation where the only adult available is one who is just coming for the packed lunch, then carefully manipulate groups so that “liability child” isn’t in their charge. If “liability adult” is the parent of “liability child”, then keep them close to a member of staff.

5 Remember the midday toilet break. It is advisable to do this in shifts to avoid frightening old people with excess crowd noise. Then do another head count. And another.

6 If for no other reason, do preliminary visits to ensure that any route taken does not go past a video games shop. This will minimise travelling time and stress put on teachers as they prise children off shop windows or, in some cases, from the free games machine inside the shop.

Children are mesmerised by these places, far more interested in them than the trip. It never ceases to amaze me that they expect their parents to pay hard-earned money for them to do what they could easily be doing at home.

7 Always take spare food - from the school kitchen - as some parents think that a packed lunch means giving their child a couple of pounds to get something from the shop on the way to school. And little people who always forget their PE kits usually forget their packed lunches too.

You’ll often find that one child’s packed lunch is a packet of custard creams and half a box of dairy milk chocolates and another child has forgotten his completely.

8 Make sure that you are aware of any dietary requirements and sit close to the children who have these to stick to.

I remember once a child allergic to dairy products who, despite knowing that he had this allergy, did not know what he could and couldn’t eat. After hard bargaining with another pupil, he swapped his kiwi fruit for a vanilla-flavoured yoghurt. Unfortunately the swap went unnoticed until the very last drip of yoghurt fell from pot to mouth.

Fortunately, the result of this mistake was nothing more than a very runny nose and a carrier bag full of used tissues.

Remember that children will not all finish lunch at the same time and many will have consumed a high percentage of E numbers so it’s always best to let them have a short play - great if you’re in a park, problematic if you’re sitting by the city centre roundabout. Do a head count every two or three minutes.

9 Be strict about spending money on school trips. If there is a shop to spend a couple of pounds in, include a set figure in the cost of the trip so that every one gets the same amount and you don’t end up giving all your money to the children that have none.

The second most popular question on any trip is always “Can we go to the gift shop now?” Be prepared. It can be a bunfight.

Make sure any set amount of permitted cash will actually buy something in the gift shop - they have a habit of selling very expensive tat.

Take away any extra money that the class show-off might have brought with him and threaten to take away his set amount if he continues to argue that he is being penalised for being well-off.

10 Always bring back to school the same number of children that you left with to avoid angry parents and losing your job.

Last year, during a day trip to France, a very confident boy showed me his overnight bag and said that he had planned to meet his mum in Calais and wouldn’t be coming back with us.

Unfortunately for him and his mum, he was taken back to school and his dad was surprised to receive a call to come and collect his son. The family had, in fact, made these arrangements and had not informed the school.

11 When travelling by public transport, hide 29 kids behind a bush. Only allow the bus driver to see the others when they actually start boarding. Some drivers can’t bear the thought of 30 screaming kids on board.

12 Whatever happens, whatever the crises, however awful you think your day, the kids will always think they’ve had a wonderful time, so enjoy retelling the mishaps when you get back to the staffroom.

13 Have a good bottle of wine ready to drink when you get home.

Tracey Jarvis is deputy headteacher at Ivydale primary school in Southwark, south London