“You can’t cremate any kind of electronic device like a cell phone or hearing aid or pacemaker,” says Perman.

That is only around a fifth of the power that a pacemaker requires, but Dr Singhal reckons that a human-sized version of his cell would be able to deliver enough juice.

The circadian system in mammals is composed of a master pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus and slave clocks in most peripheral cell types.