People with multiple sclerosis often have trouble controlling their muscles.

The machine, which has been developed at the Bristol MS Research Centre, can tell exactly how much weight is being placed on each foot.

It has already helped athletes and astronauts.

A computer analyses the readings from the machine and tells patients how to compensate for muscles which are not working well.

The centre has also pioneered the use of electrodes which stimulate muscles to help sufferers walk more easily.

Andy Williams hopes the machine will stop him falling over so regularly

Andy Williams was first diagnosed with multiple sclerosis seven years ago.

It is an illness which affects the way his nerves communicate with muscles, which often causes problems with balance.

"If you walk without any aid you tend to swagger, and if there is anything loose, then the foot finds it and you go over," he told BBC Bristol.

Research carried out at the Bristol centre shows half of all patients fall over as many as 20 times a year.

"People are not always aware how bad their balance is or how it's changed," said Dr Rosie Jones of the MS Research Centre.

The centre has also pioneered the use of electrodes which stimulate muscles to help sufferers walk more easily.