The Longitude Prize 2014, a challenge with a prize fund of £10m, has identified access to safe and clean water as one of six key issues on which the British public will cast the deciding vote to choose which one the prize will tackle.

The Prize, which was been launched yesterday, has been developed and run by Nesta, the UK's innovation foundation, and is being supported by the Technology Strategy Board as launch funding partner.

Longitude Prize 2014 commemorates the 300th anniversary of the Longitude Act in 1714, when the British government threw down the gauntlet to solve one of the great scientific challenges of that time: how to pinpoint a ship's location at sea by knowing its longitude.

The challenge was solved by watchmaker and carpenter John Harrison who designed the chronometer, the first seafaring clock that allowed accurate navigation. The solution not only led to safer sea travel but opened up global trade.

 Over the past two years the Longitude Committee, chaired by  Martin Rees the Astronomer Royal, has been assembled to identify some of the equivalent challenges facing the world today. The whole of the UK can now get involved and have their say in deciding which should be the focus of Longitude Prize 2014.

Water and how to ensure everyone can have access to safe and clean water as it becomes an increasingly scarce resource is one of the six challenges that the public are being invited to vote on . Forty-four per cent of the world's population and 28% of the world's agriculture are in regions of the world where water is scarce. The Longitude Prize challenge is to alleviate the growing pressure on the planet's fresh water by creating a cheap, environmentally sustainable desalination technology.

The other five issues are:

• Flight - How can we fly without damaging the environment? The challenge is to design and build an aeroplane that is as close to zero carbon as possible and capable of flying from London to Edinburgh, at comparable speed to today's aircraft.
•  Food - How can we ensure everyone has nutritious, sustainable food? The challenge is to invent the next big food innovation, helping to ensure a future where everyone has enough nutritious, affordable and environmentally sustainable food.
•  Antibiotics - How can we prevent the rise of resistance to antibiotics? The challenge is to create a cost-effective, accurate, rapid, and easy-to-use test for bacterial infections that will allow health professionals worldwide to administer the right antibiotics at the right time.
•  Paralysis - How can we restore movement to those with paralysis? The challenge is to invent a solution that gives paralysed people close to the same freedom of movement that most of us enjoy.
•  Dementia - How can we help people with dementia to live independently for longer? The challenge is to develop intelligent, affordable integrated technologies that revolutionise care for people with dementia, enabling them to live independent lives.

 Martin Rees said:

 "Science and technology have transformed people's lives for the better. But much more is needed to meet the needs of the world's rising and ageing population - and to do this in a way that avoids unsustainable pressure on the environment.

 "Three hundred years ago the Longitude Act stimulated invention and drew out hidden talent. But today there are many areas where progress is still needed. That's why we've decided that the theme of Longitude Prize 2014 should be selected in response to a public vote. We can all play a part, so I encourage people to tell us what their number one challenge is."

On 22 May, BBC Two will broadcast a special 50th anniversary show of Horizon which will profile the Longitude Prize 2014, detailing the challenges and telling people why they should be solved. After this, people will be able to vote for the challenge they feel is the most important at www.bbc.co.uk/horizon

 By the end of June, the public vote will have decided which challenge will be given a £10m pound prize fund and up to five years to find a solution.

For more information sign up to the newsletter at www.longitudeprize.org.