Counterfeit computer chips could pose a threat to military computer-based hardware and systems, crippling or disabling them, U.K. experts say.

A U.K. electronics firm discovered that a classified avionics system it makes for military aircraft failed when it was installed in a test plane, NewScientist.com reported Tuesday.

Upon investigating, it found many of the connecting pads on a key microchip were not connected to the metal legs of the chip carrier, the plastic package that houses and protects the chip.

When the chip carrier was soldered to the system's circuit board, the entire system failed to work.

What made it shocking, a company source told NewScientist, was that the chip was supplied by an authenticated U.K. defense supplier.

"It was the genuine article -- but our supplier had the chip bonded by an unqualified third-party outfit which has now disappeared," the source said.

Because a chip carrier is a sealed unit, counterfeit carriers with no chip at all are also becoming commonplace, says the source.

Other fakes are reclaimed from recycled circuit boards and printed with the markings of expensive military-grade chips.

In November a Florida woman pleaded guilty to taking part in the sale of $16 million worth of such rebranded counterfeit chips to the U.S. Navy and a multinational arms manufacturer, NewScientist.com said.

Identifying the fakes and taking action against their makers is not easy, an expert says.

"Counterfeiting operations are becoming well-oiled global machines with a complete support ecosystem around them," Ruth Thomson, a product authentication expert with U.K. R&D firm Cambridge Consultants, says.