Same issue for employee at home in Chelmsford on Tuesday.
Own router. Seemed to be a routing issue. Pings at 1sec seemed ok but huge packet loss if I tried 0.01 sec. Traceroutes disappeared into the ether.
She gave up and went to the office 20 miles away, and BT, but ok.
They had apparently been noticing similar issues for a few days but assumed it was a.n.other problem.
Joy