Update (14:53): Customers are reporting issues with Gateway Timeouts; commonalities between customers are the use of CloudFlare. We are recommending that all customers disable CloudFlare completely before raising a ticket for support.
Update (15:19): CloudFlare are reporting that a temporary fix is in place and services should resume normality.
Do not raise an emergency ticket if you use CloudFlare. Customers are advised to view https://www.cloudflarestatus.com/ and disable CloudFlare in the mean time.