Sleep has a problematic relationship with music. Its sedative effects are well known (and a hazard for the professional critic of live concerts when there is no chance of a replay) and it is used by parents everywhere as a tool to help children sleep. But the composer Max Richter has created a piece of music with which he aims both to sedate his audience and to address their subconscious by continuing to play until they wake again eight hours later. Its premiere before a recumbent, duvet-covered crowd is beginning tonight at midnight on put-me-ups in the soporific library of the Wellcome Collection, the museum of the late Sir Henry Wellcome, whose Victorian pharmaceutical company first introduced drugs in tablet form and was thus the inventor of the sleeping pill. BBC Radio 3 will broadca