Flying saucers could potentially be used to support troops engaged in urban warfare. The military is to assess whether the alien-like aircraft, Moon buggies and miniature flying robots are capable of detecting roadside bombs and insurgents without putting troops in the line of fire.

The saucers, which are less than a metre (3ft) across, have optical and infra-red cameras and can fly over enemy positions without the need for a remote-control operator.

The unusual devices are among the entrants in a Ministry of Defence competition aimed at encouraging the development of urban warfare equipment.

Eleven teams taking part in the final of the Grand Challenge, which starts today on Salisbury Plain, Wiltshire, will have the opportunity to show off their inventions in a purpose-built town that contains enemy snipers, roadside bombs, weapon-mounted vehicles and insurgents armed with rocket-propelled grenade launchers, as well as innocent bystanders.

Military analysts believe that street fighting will become an increasing part of armed conflict in the future and want to make sure that British troops have the edge. Experiences in Iraq, and to some extent Afghanistan, have illustrated the dangers of fighting in built-up areas against insurgents.

Major Matt Kelly, of the Royal Irish Regiment, said of urban warfare: “In the future there will be no alternative for us so we, as soldiers, need to know where the enemy is and why. This is where technology comes in.”

The option of sending in a robot to check what is behind a wall or to survey a town before deploying ground troops could minimise British casualties.

“If our system works it will save lives,” said Julia Richardson, who leads the Stellar team which created two unmanned aircraft and a robotic ground vehicle. “That’s what motivates us.”

The Stella system operates as a robotic team, with one unmanned aircraft mapping an enemy stronghold, and the second aircraft working with the ground vehicle to provide close inspections.

The devices, like others in the competition, are fitted with thermal and normal lens cameras linked to intelligent software that can interpret pictures to identify potential threats.

Chris Mellors, of the Mira team which developed the flying saucers, added: “The bottom line is, we want our technology to help our Forces.” The Mira team is made up of a mixture of people including BAE Systems and pupils from the Royal Grammar School in Guildford, Surrey.

Max Pengalley, whose son served in the Army, and Rob Mullins, who lost a friend in Iraq, are part of the Locust team, which has developed a foot-long aircraft with foam bodies. Both were anxious to make a device that was flexible and lightweight enough to be carried by troops on the front line. The camera, processor and radio used to beam images back to troops are the of a book of matches, and the receiver has been adapted from a handheld Satmap.

One of the more bizarre inventions taking part is the Tumbleweed Robot, which can transform from an unmanned aircraft into a rolling ball.

Raglan Tribe, of the Mindsheet team, helped to create a fleet of buggies that can whiz across rough terrain at up to 30mph as they search out roadside bombs and enemy personnel.

The buggies, like the other entries, are designed to be low-cost because, unlike the troops, they have to be expendable.

Baroness Taylor of Bolton, Minister for Defence Equipment and Support, said: “The UK has a world-class track record in scientific excellence and we want to draw on all of the expertise out there, from box-room inventors just starting out to the largest defence firms. The competition has been designed to provide an accessible and fun event for participants, but there is a very serious point to it.”

The winner of the competition will receive the R. J. Mitchell Trophy, named after the designer of the Spitfire fighter. The MoD will assess whether the inventions taking part in the final can be used on the front line.

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