Cloudflare has resolved the issue and services have resumed normal operation.
A major outage impacted all Cloudflare services globally. A massive spike in CPU caused primary and secondary systems to fall over. The process that was causing the CPU spike were shut down. Services were restored to normal within approximately 20 minutes. Cloudflare are now investigating the root cause of what happened.
A media report on the outage can be found here https://www.bbc.co.uk/news/technology-48841815