Linode London has been experiencing "greater than normal" intermittent packet loss to Akamai network which they use to peer with other player such as Cloudflare in LDN for nearly two days - before they peered with CF via Linx if I remember correctly. It isn't just isolated to UDP customers. Currently it's fairly stable so for most it's hard to notice but certainly uncomfortable how far they want to drag this problem on - see status.linode.com for how grim the LDN situation is - their support said we'll tell you in a few days what it was once we fixed it. i.e. it's not the rock solid of the last 7 years and their support are largely deaf to how unacceptable this is based on previous standards.