Oliver Soskice, 69, has previously almost got locked in the University Library.
But his latest brush with literary imprisonment came as he was perusing the upstairs sections of a Waterstone’s approaching the 7pm closing time tonight.
Suddenly, he noticed all was not right .
“I was upstairs, I was looking for something. I half noticed the place was particularly quiet but it didn’t strike me as odd,” Soskice said.
“But then when I came down there was an unearthly silence and then I realised I’d locked myself in.”
The painter, whose wife is a university professor, triggered the Cambridge shop’s lights and alarms as he tried to escape the deserted shop, Cambridge News reports.
Mr Soskice estimated he was locked inside for around an hour and 20 minutes before a manager came to rescue him.
Admitting that he had previously almost got locked in the University Library, he remained calm in the face of adversity.
He said: “I was mostly thinking how on earth do I unravel this mess I got myself into.
“I could see people going backwards and forwards. I was hoping a policeman might go by or something like that.”
After failing to reach his wife, Mr Soskice rang his daughter who suggested he ring the non-emergency police 101 number.
Officers struggled to find the correct contact numbers for the store and Mr Soskice could not locate the right button to operate the front desk telephone.
Eventually the confined painter was released from the empty shop by a manager, who said this had never happened to a customer before.
Mr Soskice remained reflective over his temporary imprisonment.
“There are worse places to be trapped than in a Waterstone’s,” he said.
“The two things that interest me are the philosophy section and the section on art.”