It started off as an ad-libbed joke for some friends in a football banter group and ended up being heard by vast numbers of Britons within hours.

But the man responsible for a joke WhatsApp audio clip that claimed the Ministry of Defence was about to requisition Wembley Stadium to cook the world’s biggest lasagne has said his viral success also shows the risks of believing everything that gets sent to you on the messaging service.

Billy McLean, a 29-year-old Londoner who works in software sales, came forward to the Guardian to identify himself as the creator of the much-shared clip mocking the coronavirus misinformation and rumours that have spread over WhatsApp in recent days.

Parodying the widespread viral posts claiming to be from friends-of-friends who are supposedly government officials with the inside track on No 10’s pandemic plans, McLean ad-libbed an audio recording in a matter-of-fact voice: “My sister, her boyfriend’s brother works for the Ministry of Defence and one of the things that they’re doing to prepare … is building a massive lasagne. At the moment, as we speak, they’re building the massive lasagne sheets.”

He added: “They’re putting the underground heating at Wembley on, that’s going to bake the lasagne, and then they’re putting the roof across and that’s going to recreate the oven, and then what they’re going to do is lift it up with drones and cut off little portions and drop it off to people’s houses.”

Play Video 1:15 Billy McLean's joke about a 'massive lasagne' went viral on WhatsApp – audio

He sent the clip, at 1pm on Thursday, to a group of 30 friends he plays football with. Some of them then forwarded it to friends and relatives in other groups. Hours later, it was being sent back to McLean by friends who had no idea it was his voice, having travelled around the world in the intervening hours.

McLean said: “It was just a one take. I sent it to the football group, my mum and the girl that I’m trying to date.

“It went around the football group. Then I got people that I know forwarding it to me, not knowing it was me, or forwarding it to me asking if I’d heard it. Ex-girlfriends were coming out of the woodwork asking was it me.”

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By Friday morning, the Football Association was able to confirm that, yes, it was indeed aware of the clip but, no, it had no plans to turn the English national football stadium into a giant lasagne dish.

The spread of the clip shows both the enormous power of WhatsApp to spread unsourced information at speed and Britons’ need for something to laugh at in a grim period.

WhatsApp’s lack of an ability to track or factcheck material means that the clip was arriving in people’s messaging service as an unlabelled audio clip. Although there is no way to measure its audience, it is likely to have been listened to by millions of people within hours. Many more have since heard it after it was uploaded to other services.

McLean suggested that people needed to resist the urge to share unsourced information about the coronavirus, especially those claiming to be from insiders.

“The intentions are good but the outcome most of the time is pretty bad, it makes people panic more,” he said. “There’s no validation for what’s being said in the messages.”

He said people needed to have their wits about them when it comes to seeking out trustworthy news in the crisis: “If someone sitting at home in their boxers selling software can save a one-minute clip and make it go viral, you’ve got be aware that anyone can put anything out and it might not be valid.”