14-year-old Lauren took part and here she writes about why the protest was important to her.
"The experience of the student march was the most exhilarating that I've had.
We protested to show that the future of our country is against the war that they seem so willing to go forward with.
We went on this march to show Tony Blair that it's not only the adults that have an opinion.
The fact that over 500 students walked out of school and marched to Parliament Square conveys that this is something we feel strongly about.
Hopefully this will make our leader Tony Blair listen.
Continue to protest
In my opinion this WILL make a difference!
And if he still decides to carry on with the war we, the youth of the UK, will be peacefully protesting!"
Lauren, 14, London
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