For some children it's a coming of age thing, a way of trying to assert your independence but for some children it becomes their life and they never return home.
Did you know that it is estimated that a child runs away from home or care every five minutes in the UK
In a recent survey one in 11 teenagers aged 14 to 16 admitted to having run away overnight at some stage in their life.
It's impossible to know the true scale of the problem as two-thirds of runaways aren't reported as missing to the police, and many more are too vulnerable or scared to seek official help.
Over Christmas, a time for families, it's estimated 2000 children will have run away.
But it's not just neglected or children in care that run away. It's nothing to do with family economics or where people live, it doesn't matter if it's from a one-parent family or not, whether it's a blended family or a traditional family. For whatever reason a child will run away from home.
It's every parent's worst nightmare and it doesn't matter if you are rich or poor.
Often it is a spur of the moment decision, which means they won't have thought about where they'll go, where they'll sleep, how they'll get access to money or how running away might affect their family.
Usually, they're running away from problems at home or at school. Some are dealing with very serious issues at home, such as neglect, drugs and alcohol addiction (their own or their parents), mental health problems, violence and abuse. A few teens are even forced to leave home by their parents or carers.
Other come from perfectly "normal" family backgrounds and are trying to escape common problems such as bullying, relationship difficulties, loneliness or family breakdown.
But what teenagers don't realise is, the problems they face on the street are often worse than those they have endured at home. In many cases, children and young people who end up alone on the streets are at risk of sexual exploitation, drug and alcohol dependency, abuse and violence.
Signs that a child might be thinking about running away can vary as every child handles problems or deals with stress in different ways. But here's a list of things to watch out for if you are worried;
* Staying out later than agreed / Pushing boundaries
* Not wanting to come home from school, youth club or friends' houses
* Staying over at friends' houses more often, or staying with other family members to avoid coming home
* Playing truant, or doing less well at school
* Behaving very differently - for example, acting more aggressively or becoming withdrawn
* Developing new interests outside school, hanging around with a new crowd, or starting a new relationship
* Showing signs of alcohol or drug abuse
* Being very secretive when using the internet
You know your child better than anyone else, and none of the above signs in themselves means your child is definitely thinking about running away. But if you notice obvious changes in your child's behaviour and these are worrying you, try to talk to them and find out what's going on.
With teenagers, this is often easier said than done. If they clam up, try sending them an email or text to let them know you're worried. If they do open up, ask them what they think they should do about their problem, rather than bombarding them with advice, it might help them feel more in control of the situation.
If you can, talk to your child's other parent to get their perpective and, where possible, present a united front in dealing with the problem. If your child senses that you and their other parent disagree, they may find this even more unsettling, or they may try and play you off against each other, which could make things worse.
It's also worth having a quiet word with any other adults your child spends time with, such as their teacher, youth worker or friends' parents, so the can let you know if they notice anything unusual.
However if this doesn't work and you think your teenager has run away and you can't get in touch with them, then the main thing is to try not to panic and go into a meltdown. Teenagers are prone to strops and storming out, so, difficult as it may sound, do your best not to jump to any worst-case conclusions, as the vast majority of child runaways return safely.
Here are some suggestions that members of Mumsnet as well as advice from Railway Children (see below), as to how to respond if your child runs away.
* Ring around their friends and see if your teen is there. Ask to speak to the friends' parents too
* As soon as you're sure your teenager is missing, contact you local police as soon as possible by dialling 101. (The 24hr waiting period doesn't exist for under 18s)
* Phone the school and see if it can shed any light on new friends your child might have been hanging around with, or places they might have been going. You can also ask the school if they can tell you if any of your teenager's friends are also absent that day.
* Have a look at your child's Facebook wall (if they have one) to see if there's any information there and check their internet history for any clues.
* Send a text message that reassures your teenager the situation can be resolved, and letting them know you love them, to encourage them to get in touch. Avoid angry or confrontational messages
* Spread the word to as many people as possible that your teenager is missing
*Make a note of any clothes or personal items that are missing.
Once you report a missing child to the police the police will take a report from you, enter the information into their system and circulate the person as "missing"
If the person cannot be found by the immediate enquires made by the Initial Investigating Officer, an officer with the police station will look after the case. This will include checking to make sure they have all the details.
Things you may be asked to include are:
* Details of the missing teenager's friends or relatives
* Places they're known to visit
* Any health or medical conditions they have
* Recent photographs
* Recent events that could be connected to their decision to run away
* A DNA sample (from a toothbrush for example)
Officers will also ask for permission to search your home for any more evidence or leads as to why your teen may have gone, which is normal procedure. They will also ask for your permission to make public the fact that your teenager is missing.
Railway Children is an international children's charity. It fights for vulnerable children who live alone at risk on the streets, where they suffer abuse and exploitation. In the UK, society often denies their existence, and in other countries the problem is big that it has become "normal".
Here in the UK, Railway Children helps and supports children under 16 who've run away from home, or at risk of doing so. They also support children after they've returned home or gone back into care. And they help educate young people about the risks of running away and what the alternatives are.
Railway Children provides funding and support to local organisations whose familiarity with their areas means they can quickly identify any new children arriving on the streets. The charity also funds social research to make sure the issue is high on the agenda for Government and policy makers.
*** This information was compiled with thanks from Mumsnet who are working with Aviva and their charity partner Railway Children. Aviva has also promised that for every Mumsnet blogger who blogs about Runaways, they will donate £2 to Railway Children and for every comment on the blog post they will donate another £2 so please please do comment if you have read this post and help raise as much as we can for Railway Children and all the work they do to help runaways, because you never know, the next teenager they help might just be yours! ***