An Oxford educated university professor aged 61 leads a secret double life as an x-rated porn star.

Nicholas Goddard, a chemical engineering teacher of almost 25 years, is also known under his adult movie name of Old Nick.

For the past decade the divorced dad-of-three has starred in dozens of skin flicks.

Some of the pornographic films, in which the professor enjoys steamy sessions with girls 40 years younger than him, have been viewed millions of times.

Double life: Nicholas Goddard has been uncovered as a secret porn star

But in his day job, Prof Goddard teaches students at the University of Manchester.

A source told The Sun he was "very pleasant" and "quite nerdy”.

“It’s not exactly a smart move to be teaching 18-year-olds by day and having sex with others at night. Some students will think he’s a hero and has the dream hobby, but the university will be furious," the source added.

But Prof Goddard described any complaints about his second job as "hypocrisy".

During evenings and weekend 75 per cent of the university's web traffic is on porn, he added.

The academic got into the adult entertainment business following the stress of his divorce.

He said: “I don’t get paid much, mainly travel expenses.

He added: "What I do in my private life is my business not the university’s. I haven’t told anyone there.

“I don’t know what students or their parents would think but I for one certainly wouldn’t care if my children were being taught by a porn star.”

The university confirmed Prof Goddard was a member of staff and they knew about his second career.