Boffins have proved that it is possible to down an airliner from the ground using a homemade pulse weapon made from bits bought on the internet.

Yael Shahar, director of the International Institute for Counter-Terrorism in Herzliya, Israel analysed electromagnetic weapons in development or used by military forces worldwide. They think that there is low-cost gear available online that can act in similar ways.

All the terrorist would have to do to fry a plane's electrical system is to send out a single but highly energetic microwave radio pulse blasted from a device inside a plane, or on the ground and trained at an aircraft coming in to land.

Gear being developed by the US and Russian military includes electromagnetic pulse (EMP) warheads that create a radio-frequency shockwave. The radio pulse creates an electric field of many hundreds of thousands of volts per metre, which induces currents that burn out nearby electrical systems, such as microchips and car electronics.

Shahar said that once it is known that aircraft are vulnerable to particular types of disruption, it isn't too much of a leap to build a device that can produce it. And much of this could be built from off-the-shelf components or dual-use technologies."

EMP generators can be built from descriptions available online, using components found in devices such as digital cameras. It makes making people take their shoes off or confiscating their yoghurt at airport security seem the pointless, bureaucratic, bit of jobs worth stupidity that it really is.