Last Thursday, distracted by a mound of paperwork, I left the children to their own devices. They did what you might expect any boys of 10 and 13 to do — slobbed around the TV and PlayStation and snacked on Rich Tea biscuits. It was only at 4pm, when they finally roused themselves to kick a football in the garden, that I realised they were still in their pyjamas.

Oh, the bliss of summer holidays! Like every household with school-age children, ours has, over the past six weeks, wound down to a state of sublime idleness. No homework or music practice, no flitting from tennis to swimming, no lunchboxes to prepare and mud-encrusted sports kit to wash.

Mothers, in my experience, fall into one of two camps — those who can’t wait to shove their children back through the school gates, and those who wish the holidays could be stretched into late September. When my own children were at the demanding, bickering, energy-sapping stage, obviously I was among the former. Now that they can make their own toast while I read the papers in bed, well, why would I be in a hurry to restore the tyranny of the school run?

The start of term is looming, however, and it is time to sew on name tapes and snap out of slummy-mummy mode. “For any mother, I think September, not January, signals the real new year,” says Kate Figes, author of The Terrible Teens and mother of two teenage girls. “I’m always in a state of denial because it is such a bittersweet time. The children suddenly seem older. Their uniform doesn’t fit. Their new shoes are impossibly big. I know that they are secretly thrilled to go back — but I always feel that I am saying goodbye to a little bit more of them.”

You may feel similarly sentimental, but the only sensible way to get through the next fortnight is to adopt the approach of Justine Walsh and Kim Nicholson, two former London nannies whose style — think Mary Poppins crossed with Fearne Cotton — has turned them into quasi-celebrities in America. Their recently published book, Nanny Wisdom (with a foreword by Justine’s erstwhile employer Richard Gere), devotes an entire chapter to mobilising your children — and yourself — in preparation for the new academic year.

“It’s great to have the unstructured time of the holidays, but we’ve always found that it is best to maintain some order, otherwise school time can come as a terrible culture shock,” says Justine, 37, who grew up in South London and has been a nanny for 18 years. “If you haven’t already done so, now is the time to introduce some rituals.”

The starting point must be bedtime — often the first thing to slip when school is out. “If your children are going to bed an hour or two later than normal, you need to pare that back gradually,” says Australian-born Kim, 31. “With young children — the under-7s — you should start well ahead, up to four weeks before school starts. The older ones will need a week or so in which the days are structured and calm, there are no sleepovers, and bedtime reverts to the term-time norm.”

For those who have children starting school for the first time, additional forethought is required, particularly if they do not have older siblings to tell them how great it is going to be.

Walsh and Nicholson prudently advise a visit to the school, the organising of play-dates with children who are going to be in their class and the reading of appropriate books — Eric Hill’s Spot Goes to School is a perennial favourite. Children who have already learnt to take shoes on and off, dress themselves and use the loo with minimum assistance will be more confident. “Talk about school, but don’t build it up too much, because that is likely to make your child anxious,” says Justine. “And be wary of well-meaning relatives who might put thoughts into their heads that they would never have dreamt of themselves. Remarks such as ‘I’m sure you’ll have a nice teacher’ may suggest to a young, impressionable mind that some teachers are monsters.”

If you are feeling tearful come the first day, practise self-restraint. “He or she may wobble, but it will be ten times worse if you cry, too,” says Justine. “Don’t sneak off without saying goodbye, but don’t linger either. Keep the parting short and sweet, and remember that any tears from them are likely to stop once you are out of sight.”

For children of all ages, the organising of pencil cases, haircuts and buying of school shoes can serve as signals of the timetabling that lies ahead. Walsh and Nicholson have another suggestion that will make you feel less harried Lynette and more Bree Van de Kamp. Find a spot in your kitchen for a chart upon which you can create a checklist of the items each child will need every day — Mondays: sports kit and return school library books; Tuesdays: show-and-tell for Luke, ballet shoes for Kate; Wednesdays: piano books for Rebecca . . . and so on.

“It’s all about eliminating those mad morning panics when you leave the house wondering what you’ve forgotten,” says Justine.

Walsh and Nicholson’s other super-efficient tips include making sure that you are up a good 20 minutes before the children. The breakfast table should be laid out the night before, as should uniforms, while packed bags are placed by the front door. “We have a very firm ‘no TV’ rule on school mornings. No one can be expected to compete with television for a child’s attention,” says Kim. “We also like children to wash and dress before coming down for breakfast, so that everyone can relax while they eat rather than watching the clock.”