A global IT outage is “likely” to occur again unless governments and industry work together to “design out” technological flaws, a leading cyber expert has said.

Professor Ciaran Martin, the former chief executive of the National Cyber Security Centre (NCSC), said “the worst” of the global IT outage was over but countries would “have to learn to cope” with future flaws.

The founding chief executive of the NCSC told Sky News: “The worst of this is over because the nature of the crisis was such that it went very badly wrong, very quickly. It was spotted quite quickly and, essentially, it was turned off.”

System failure caused by the global IT outage reportedly led to a massive grid-lock at the US-Mexico border with even approved Border Protection vehicles stranded for about 90 minutes.

Officials turned to workarounds like colour-coded cards to streamline processes, San Diego Union-Tribune reported.

The outage also led to employees working with US government agencies missing work at the US border.

“Due to the global Windows outage, some of our staff are experiencing major delays getting across the border to come to work. This may result in missed or delayed service,” the San Diego Metropolitan Transit System posted on X.

CrowdStrike said a significant number of the over 8.5 million devices affected by last week’s botched software update are back online, Reuters reported.

Over the weekend, Microsoft deployed hundreds of its engineers to help its customers restore services after the global IT outage caused by its cyber security partner CrowdStrike.

Microsoft said over 8.5 million devices were affected by the outage, which led to airlines, banks, call centers, transportation and healthcare systems struggling worldwide.

CrowdStrike said the outage was caused by a defect in an update to its “Falcon” cybersecurity defence software for Windows hosts.

More than 1,500 flights were cancelled for the third straight day in the US yesterday amid a global tech outage due to CrowdStrike’s botched software update.

Thousands of passengers were left stranded at airports across the US as nearly 1,600 flights travelling within or out of the US were cancelled, and about 8,500 delayed on Sunday, data from flight tracking website FlightAware.com suggests.

Delta Air Lines chief Ed Bastian said the company is still working to recover its system and restore operations.

“Canceling a flight is always a last resort, and something we don’t take lightly,” Mr Bastian said.

The CEO of Crowdstrike, the company at the centre of the global IT outage, confirmed that the issue affecting millions of Windows devices “was not a security or cyber incident”.

Posting on the social media platform X on Friday afternoon, George Kurtz said: “Our customers remain fully protected.”

Normal GP service “cannot be resumed immediately” after Friday’s global IT outage caused a “considerable backlog”, ​the British Medical Association has warned.

The trade union for doctors said GPs would “need time to catch up from lost work over the weekend”, adding that NHS England should “make clear to patients” this was the case.

The British Medical Association (BMA) said its GP committee would continue to talk to NHS England and patient record system supplier EMIS to secure a “better system of IT backup” to ensure the “disaster” was not repeated.

It is something the former deputy prime minister Oliver Dowden, warned of when he made the case for us to all think about how prepared we are for prolonged disruption during a cyberattack. While, George Kurtz, the founder and chief executive of the cybersecurity firm CrowdStrike, has made it clear there was no possibility that this power outage was a cyber-attack it has certainly focussed our minds.

It is also a reminder of the smash Netflix hit Leave the World Behind which pondered the stark, post-apocalyptic depiction of the immediate aftermath of an attack. In the movie, the first time anyone notices that something is wrong is when they discover their mobile phone coverage is out, and their wifi disappears, but it takes a push notification on their TV screens for the characters to learn that an attack has been launched.

Chris Stokel-Walker reports: