Fifty years ago, humans took their first steps into space with the launch of the Russian satellite Sputnik. Now scientists are urging the Government to send British astronauts into space by the 2020s. Britain is being left behind as countries around the world head into space, according to the report from the panel of scientists and industry experts, appointed by the British National Space Centre.

Oxford University Professor of Physics Frank Close, who chaired the UK Space Exploration Working Group (SEWG), said sending humans into space was about more than collecting scientific data. It could also inspire the nation and future generations.

Speaking at the BA (British Association) Festival of Science at York University, he said: "The concept of human exploration of space is inspiring, and UK involvement could add a level of pride and encourage the young.

"There is a real crisis in the numbers of kids taking science and engineering subjects at GCSE and entering university. This has been falling, and if something doesn't turn it around then 50 years from now we won't have qualified engineers."

He pointed out that the European Space Agency already had an astronaut corps, and the US, China and India all planned lunar landings. All the G8 developed nations were active in human space exploration except for the UK.

Prof Close added: "By doing the hard stuff we stretch ourselves as a nation, and that's what it's all about."

Prof Close said there were four stages to space exploration. Britain had already participated in three - making observations with telescopes, sending out unmanned orbiting probes, and landing robot craft on the surface of other planets.

The fourth stage involved human space missions. "The ultimate goal would be to have humans on the spot, doing exploration and surveying and research," said Prof Close.

"The space-faring nations of the world now recognise it is possible. This is the time that science fiction can become science fact. Our study is recommending that the UK be actively involved in both the robotic and human aspects of this collaborative international venture."

Professor Monica Grady, from the Open University, who chaired a sub-group of scientists on the working party, said: "Everything hinges on the most profound challenge that humanity has, which is the quest to understand the origin of life and whether there is any life beyond the Earth. This is a question that unites scientists from every discipline, from astronomy to zoology."

She said human space missions could make an enormous difference to this kind of science. The Moon, for instance, was conceivably the "greatest archaeological site in the Solar System".

British scientists already involved in this quest include those at Culham-based Scientific Magnetics, which is making a magnet system for the Alpha Magnetic Spectrometer (AMS) space instrument, intended to track cosmic rays to unravel secrets of the universe such as so-called 'dark matter'.

Peter Penfold, of Scientific Magnetics, said: "If Britain could do more in space, that would make us very happy. Britain is not contributing to the AMS experiment, while other countries such as Russia, Taiwan and China have joined."

His company's work for AMS, expected to launch in 2009, is funded by universities and research centres all over the world, but none of the 56 scientists involved is in Britain.

Work on the instrument was started by Oxford Instruments, which spun off the work to a new company headed by engineers Stephen Harrison, Stephen Milward and John Ross.

Mr Ross has now retired and the ten-year project is almost complete, with the instrument on schedule for delivery from Culham to the European science collaboration Cern in Geneva next summer.

Mr Penfold said they had funding from the US Department of Energy as well as Britain's physical science research council. "At the moment, we create high-tech jobs in the UK using other countries' money, and that's perhaps not a bad thing for the UK," he said.

What could be Britain's biggest contribution to the space race, according to its supporters, is Skylon, being developed by another company at Culham, Reaction Engines. It aims to use a technology developed for nuclear fusion to create a "space plane" that takes off like a normal aeroplane, but then turns into a rocket when it goes into orbit.

The company was set up by aerospace engineers Alan Bond, John Scott-Scott and Richard Varvill, who were involved with Britain's Hotol (Horizontal Take-Off and Landing) space project, abandoned in 1992 by Margaret Thatcher as too expensive.

Now 63, Mr Bond says they spent years "in the wilderness" but he now believes their plane, Skylon, could be Europe's next spacebus, costing 100 times less than other technologies.

The company's heat-exchanger, smaller and lighter than conventional ones, could also be used for more environmentally friendly aerospace engines, which the engineers are exploring with the help of an EU grant.

The company has spent about £5m on Skylon, financed by directors' loans, share investment, and the sale of consultancy. Reaction Engines moved to Culham six years ago following an investment by aviation enthusiast Paul Portelli, founder of World's End Tiles, of Battersea.

Mr Bond said: "One of the things that is disappointing is that reusable launchers are still not accepted. Everyone - NASA and the European Space Agency - is taking themselves into a situation for the next 30 years where they are going to continue to develop expendable launch rockets."

He added: "Britain is no longer capable of doing anything like this on its own, but we are fortunate in having reasonably wealthy people who have a visionary view of the future."

"We seem to be the only people left who can do a resusable launch vehicle. My hope is that by 2020 Skylon, or something like it, will actually be in development. If people want to go to Mars or the Moon on a regular basis, we have to have much cheaper transport than we have at the moment."

Dr David Williams, director general of the BNSC, said the agency would carefully consider the report before deciding on its official recommendations to the Government. The cost of a five-year programme from 2010 to 2015 including manned space station missions would be around £50-£75m.

This could be paid for by a contribution of 50p a day by everyone in the UK, according to the report.

Dr Williams said: "What we need to do is look at what is said and decide whether decisions that have held for 20 years are still valid or should be revisited," he said.