Porn is ravaging young men’s sexual performance and causing teenage boys to suffer the erectile problems usually experienced by middle-aged men, a love doctor has warned.

Sex therapist Angela Gregory has seen a huge surge in the number of porn-addicted millennial men seeking treatment for their penis problems.

“What I’ve seen over the last 16 years, particularly the last five years, is an increase in the amount of younger men being referred,” she told the BBC.

“Our experience is that historically men that were referred to our clinic with problems with erectile dysfunction were older men whose issues were related to diabetes, MS, cardiovascular disease.”

“These younger men do not have organic disease, they’ve already been tested by their GP and everything is fine.”

Smut junkies pay a heavy price for their addiction.

Young men may face performance anxiety after comparing their relatively puny penises to the gigantic appendages sported by porn stars.

They may also become hooked on extreme porn depicting acts that few women would be willing to endure, leaving them bored by the standard sex on offer with real-life partners.

The problem is compounded by the omnipresence of online pornography, which means extreme content can be found free of charge in little more than a few clicks.

Gregory advised her fellow love doctors to quiz men with erectile problems about their pornographic predilections before recommending treatment.

She added: “One of the first assessment questions I’d always ask now is about pornography and masturbatory habit because that can be the cause of their issues about maintaining an erection with a partner.”

The Beeb spoke to 15-year-old Nick, who spent up to two hours a day gorging on extreme pornography.

He said: “What I was watching, it definitely got more extreme over a short period of time in my case.

“There was nothing that would give me a kick. Normal stuff didn’t do anything anymore, so I had to get more and more extreme material.

“I found that when I was lying next to a girl a lot that I just wouldn’t be horny at all, despite being really attracted to the girl and wanting to have sex with her, because my sexuality was completely wired towards porn.”

An expert weighs in on when it’s time to worry: