A British university researcher has done what the FBI claimed was impossible by unlocking an iPhone - for just £75.

Earlier this year the US agency took Apple to court - and sparked a worldwide privacy debate - as it fought to get the iPhone of San Bernardino terrorist Syed Rizwan Farook unlocked.

Eventually the court case was dropped after the FBI paid a security firm an estimated £900,000 ($1.3m) to access the device.

But Cambridge University's Dr Sergei Skorobogatov has demonstrated how to crack the password on an iPhone using only equipment available in a typical computer shop.

The key to Dr Skorobogatov's method was to "mirror" the NAND Flash chip onto a second chip, which when tweaked gave him unlimited attempts to guess the phone's password.


Most iPhones lock after 10 unsuccessful attempts to enter the code.

Dr Skorobogatov said he believed it would take about 20 hours to unlock a phone with a four-digit code and three months for a phone with six-digit security.

He demonstrated his technique in a video and wrote an academic paper, saying: "The process does not require any expensive and sophisticated equipment.

"All needed parts are low cost and were obtained from local electronic distributors."

Farook and Tashfeen Malik killed 14 people at a Christmas party in San Bernardino, California, in December 2015.

Despite the court battle, the FBI later admitted nothing of significance had been found on Farook's phone.