All of you wake up each day and maybe look at the weather or think of problems that you face, which may be personal, physical, social or even school work!! No doubt many of you complain about these problems. But how many of you are truly positive about the opportunities and challenges that crop up on a daily basis? Very often, young people like you do not realise the possibilities that exist day by day to make a real difference to your lives and even more importantly the lives of others. Each one of you has the power to make a difference, to make a positive change for the better on a daily basis, and yet I wouldn't mind guessing that not many of you are really aware of these opportunities, or have attempted to act on them.

People say it's impossible to see into the future. I disagree. The future is always predictable to an extent. Let's take some simple examples. Generally speaking, the harder you work or the more you try the more likely it is that you will be successful. The more successful you are the more likely it is that you will have a happier and better quality of life. On the other hand, the less effort you make, the less likely you are to be successful. This is not a certainty, but it is a probability. All that you do has consequences, in the same way that all you do not do also has its consequences. As most of you know, if you smoke, drink excessively, eat particularly fatty or sweet foods and do not exercise then you will become increasingly unhealthy. It is highly probable that you will die earlier - you will not live as long as someone who doesn't smoke, drinks moderately, eats five or more pieces of fruit each day and exercises for more than 30 minutes at least three times a week. What happens in years to come, happens as a consequence of what we do, or don't do today. This is a probability - in other words it is predictable.

The good news is that all of us here have the opportunity to change and start making positive differences to our lives today. We all know the old expression 'turn over a new leaf' and I suspect many of you often say to yourselves 'I'm going to do it - but not today. I'll start tomorrow…or next week… or next month'. This is commonly applied to exam revision! You must remember that success is not a destination, but a journey. In other words, getting fitter or gaining knowledge is a process which takes place on a day by day basis. If you were to exercise today then you are already in the process of getting fitter. If you work harder today then you are already in the process of being more successful in your exams.

In this country we have opportunities to change our lives because we live in a privileged society, but most of us take these opportunities for granted. Millions of children - the same age as you - do not have the opportunities that you have. Whenever you are beginning to feel that life has not treated you fairly then you need to be aware of some facts and figures which illustrate what it is like to live in other parts of the world. Some of you may have problems and misfortunes, and I am not belittling these, but equally there are many others who have even more serious day-to-day issues to contend with. Problems that go to the very heart of human existence - survival!

One small example is access to safe drinking water and provision of latrines or toilets. I doubt if you have ever needed to give this a second thought, but for many children in other parts of the world these basics are considered to be luxuries. A child dies every 15 seconds from diseases attributable to unsafe drinking water, appalling sanitation, and generally unhygienic environments.

At the same time as we argue about what vaccinations to have, elsewhere two million children die each year from diseases such as measles, polio, tetanus, whooping cough, tuberculosis and diphtheria - all of which can be easily prevented with the right measures. In this country these diseases have been largely eradicated through immunisation. In other parts of the world more than 30 million children have not been immunised, either because vaccinations are unavailable, or because families are uninformed or misguided through a lack of education.

A lack of education is also at the heart of one of the world's other major diseases. HIV/Aids is essentially a young person's disease. Nearly 12 million 15-24 years old are living with HIV/Aids and at least 2.5 million children under the age of 15 are also infected. Of the five million new infections estimated last year at least half were among the 15-24 age group. Two thirds of those were young women. More than 20 million people are living with the virus world wide, infection rates are growing rapidly, and there is currently no cure for HIV/Aids. Without better education and awareness and heroic efforts to stop the spread of the virus we as the global community face an unprecedented catastrophe.

You may grumble about coming to school each day, but you must remember that you are extremely privileged compared to the 250 million children between the ages of 5-14 who work each day. One in three children in Africa work each day, one in four children in Asia work each day, at least 120 million children work full time and, out of interest, the vast majority of those working are girls - this means they can neither go to school nor learn a trade, or even have time to play. Some of the older ones amongst you may be quietly thinking - 'I wouldn't mind working each day' - but then you also need to realise these children are working for a pittance or no pay at all, for example as farm labourers or domestic servants. For children like these, the opportunity to go to school represents their only real chance to escape a future of poverty and disease, but the prospect of it ever happening appears to them as an unachievable dream.

But this is where you come in. You all have the power to make a change, to make a difference today. Schoolchildren for Children aims not only to promote a healthier lifestyle amongst youngsters of school age but also to raise money for extra-curricular sporting activities in this school. At the same time it aims to raise money for the education of children in developing countries through books, equipment, facilities, school meal programmes, and even a gap-year scheme for volunteers working in developing countries delivering education programmes before, or after, going to university. Millions of children in these countries need your help. Unfortunately, for many of these children there is a bleak predictability and certainty about their future unless we can unite together to help make a positive change to their lives. They are destined to a struggle for survival amidst poverty, disease and starvation, unless we can make a difference. You may not have realised it but you have the power to make that difference and at the same time improve the quality of your own life. On Friday, 29th September at lunchtime, Schoolchildren for Children is aiming to unite one million schoolchildren across the UK to exercise at the same time - to walk, jog or run a minimum of a mile to raise money for all those children in developing countries. Other additional activities and fundraising events can also be done on other days. At a time when youngsters such as yourselves are often seen in a negative way, with a negative image, this is an opportunity for you to clearly demonstrate that you can work positively to benefit the lives of disadvantaged young people worldwide. This could be a very special day. Please be part of it and make the biggest effort that you can.