Engineering students in London have come up with a concept that makes it possible to erect solid emergency shelters on demand.

The shelter comes in a bag - or more precisely, in a sack of cement-impregnated fabric - and to erect the structure, you simply have to add water to the bag and inflate it with air.

It takes 12 hours before the cement has dried out and is ready for use.

The idea was developed by William Crawford and Peter Brewin when they were thinking of an entry for the annual British Cement Association competition for new and innovative uses of concrete.

• Wired