Australian euthanasia advocate Philip Nitschke has been released after questioning by British airport authorities and allowed into the UK.
Dr Nitschke, the founder of the Exit International organisation, was questioned on arriving in London with wife Fiona on Saturday for a series of public meetings and workshops on voluntary euthanasia to be held around Britain.
He expressed surprise at having been detained and questioned as he has been allowed into the UK to hold lectures before.
Dr Nitschke said he was searched, fingerprinted and formally interviewed after being told his workshops could be in breach of British law, which had not happened on his previous visits.