The explanation offered shortly before the event by Radio 4 was that Martin Creed had chosen that time for bells to ring out all over the UK because 8.12 was 12 hours before 20.12.  Is that an explanation that explains anything?  Maybe to a Turner prize winner it makes sense.

But I had no wish to be curmudgeonly so at the 12th minute of the 8th hour of the 27th day of the 7th month I rang the nearest thing I had to a bell, my phone.