by Sophie Cross

So, if the latest research on sleeping is correct, all children in southern Europe are in real trouble and the future of these countries that are already suffering rests on the shoulders of kids who just don't sleep enough.

Having lived in southern Spain for the last year, I have fought a daily battle with my daughter to get her to go to bed at what I think is a reasonable and "normal" time – for my own Northern European/Sydney standards. This is made very hard when the local Spanish children are still up at the plaza playing noisily until midnight (in the holidays), 10.30 or so in term time.

And no they don't go to school later. They go at the same time. They apparently have a siesta, but basically they just don't sleep. Which is possibly why they're generally shorter than northern Europeans. Don't you grow when you sleep?

Anyway, yes I try to get my daughter to bed at a reasonable, regular hour and Hallelujah. At last some research that backs me up and I can read verbatim to my 9 year old when she tries to stay up late again.

Apparently, late nights and lax bedtime routines can blunt young children's minds, research suggests.

Sophie Cross is a public relations consultant and writer who has publicised and written about everything from makeup to The Muppets, child care to celebrity chefs and perfume to Partners in Population and Development! Originally from the UK and as a languages graduate she has worked around the world, living in Australia for the last 11 years where she runs, PR Chicks.

She lives and works remotely from her little piece of Spanish heaven in Chite, the Lecrin Valley, just south of Granada. And FYI it's pronounced "ch-ee-tay" not shite.

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This comes from a study into sleep patterns and brain power that has been conducted in the UK on more than 11,000 seven-year-olds.

The study found that kids who had no regular bedtime or who go to bed later than 9pm had lower scores for reading and maths than those with strict bedtimes or who are in bed and asleep before 9pm.

The theory is that lack of sleep may disrupt natural body rhythms and impair how well the brain learns new information. Data was gathered on the children at the ages of three, five and then seven to find out how well they were doing with their learning and whether this might be related to their sleeping habits and study author Professor Sacker (Sacker, not Slacker) says that establishing a good bedtime routine early in childhood is probably best, but it's never too late".

Erratic bedtimes were most common at the age of three, when around one in five of the children went to bed at varying times.

By the age of seven, more than half the children had a regular bedtime of between 7.30 and 8.30pm and overall, children who had never had regular bedtimes tended to fare worse than their peers in terms of test scores for reading, maths and spatial awareness.

The impact was more obvious throughout early childhood in girls than in boys and appeared to get steadily worse over time.

The researchers, led by Prof Amanda Sacker from University College London, said it was possible that inconsistent bedtimes were a reflection of chaotic family settings and it was this, rather than disrupted sleep, that had an impact on cognitive performance in children. And of course that could well be the case, but they did try to take this into account.

The children with late and erratic bedtimes came from more socially disadvantaged backgrounds and were less likely to be read to each night and, generally, watched more TV - often on a set in their own bedroom.

After controlling such factors, the link between poorer mental performance and lax bedtimes remained.

Prof Sacker says that the take-home message is really that routines really do seem to be important for children and that "establishing a good bedtime routine early in childhood is probably best, but it's never too late".

She said there was no evidence that putting children to bed much earlier than 7.30pm added anything in terms of brain power, which is lucky because it's nigh on impossible to do this, particularly in the Summer and after kids learn to tell the time.

Dr Robert Scott-Jupp of the Royal College of Paediatrics and Child Health added: "At first glance, this research might seem to suggest that less sleep makes children less intelligent, however, it is clearly more complicated than that".

And here's the winner: "While it's likely that social and biological brain development factors are inter-related in a complex way, in my opinion, for schoolchildren to perform their best, they should all, whatever their background, get a good night's sleep", says Scott-Jupp.

And so say all of us. And if this research helps me persuade my daughter to go to bed earlier than her Spanish friends, then great! Early to bed is not only good for children's brains; it's also imperative for the sanity of their parents! The more brain developing sleep they get, the more downtime we get. It's a win – win situation.

The findings are published in the Journal of Epidemiology and Community Health.