It started on 1st Jan - any banks which won't/can't are excluded from BACS altogether I think (I had a communication from Nationwide stating that I would no longer be able to send payments to Tesco Savings because of it - Tesco Bank very quickly managed to change its systems to accommodate the new rule...)
Anyway - have just found it was because of a new EU regulation: "the European Union has said that all UK banks and building societies must reduce the time it takes to transfer payments between certain accounts"
Fancy that. How come the UK Govt didn't manage to impose this rule years ago? 