GPs couldn't treat patients, people were stranded as planes couldn't get off the ground, and small businesses lost much-needed sales.

Two months on from the global IT outage on 19 July, its full impact is only now becoming apparent.

A rogue software update by the US cybersecurity company CrowdStrike crippled up to eight and half million computers using Microsoft systems around the world.

Adam Meyers - a senior executive at CrowdStrike - will testify at the US Congress on Tuesday.

He will speak of being "deeply sorry" about what happened, and his company's determination to "prevent it from happening again."