I had some lower performance last night, didnt show on tbb graph, there was jitter as well but not severe but was defenitly there, I got the throughput back by cycling ppp to a better gateway but that wasnt enough to ditch the jitter.
On my traceroute the problem looks between these 2 hops.
Doesnt look local to me but rather within BTs network somewhere.
5 6 ms 6 ms 6 ms bt.internal [217.41.169.207]
6 6 ms 12 ms 7 ms bt.internal [217.41.169.109]
The jitter seen in hop 7 carried on to the end. All hops before hop 5 had no jitter.
BT Infinity 2 Since Dec 2012 - Estimate 65.9/20 - Attainable peak 110/36 - Current Sync 71/20