BT broadband seems to have been rather unreliable today.
I've been working at home OK, but noticed various periods of very slow performance. I was though using a VPN, and therefore not reliant on BT DNS servers
Later this evening - perhaps 7pm onwards I was not using VPN and DNS has been consistently failing. I've noticed that the connection at various times is normal (low latency), poor (high latency 250-500ms) or dead. rebooting the router (HH5a) hasn't helped. The VDSL connection itself (HG612) has been rock solid for 50 days. Manually disconnecting/reconnecting from the router hasn't helped either.
I can only guess that there are issues - yet no tweets from @BTcare, no responses, nothing here & nothing on the status page (for my area).....