Son opens 21st birthday card and discovers his last three years have been a lie

A British man was left utterly gobsmacked after opening a 21st birthday card – only to discover he'd been the butt of a family joke for the last three years.

Sarah Austin took to TikTok to share the rib-tickling moment from her son Charlie's milestone celebration, which has since become an internet sensation. The video kicks off with the birthday boy unwrapping a massive card from his parents, who prompt him to "read it out".

"Happy 21st birthday, Charlie," he read aloud, unaware of the surprise that awaited him. "Yay - you no longer have a black box." Overjoyed by the thought of being free from the driving restriction, Charlie leapt up in excitement – but the truth was yet to be unveiled.

As he delved back into the card, Charlie's expression changed dramatically: "I've had no black box for three years? Are you serious?" Gales of laughter filled the garden as he let slip a few choice words.

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Finishing the card's revelation, Charlie exclaimed in disbelief: "Are you taking the p***? You're telling me it took six-and-a-half hours to get to Cornwall?" His dad cheekily retorted: "It slowed you down though, didn't it?".

Charlie then quizzed the other partygoers if they were privy to the prank, and they all admitted their involvement. "We knew for years," one mate said with a grin. "When you had to slow down the other day, I was crying laughing!".

The clip has racked up an incredible 1.7million views despite Sarah boasting just over 500 followers. TikTok users flocked to the comments section, with many applauding Charlie's parents for their approach.

"Fantastic parenting! 3 years safe driving in the bag," one person declared. Another chimed in: "Three years of driving carefully and avoiding accidents. Three years of experience on the roads. Top parents right there."

A third person praised: "This is how to parent! Learning how to actually drive safely is invaluable."

Cinch explains what these monitoring devices actually do: "A black box is another name for a telematics unit that's fitted to a car to record how a car is driven. This data determines how safe a driver you are and is then sent to your insurer, which uses it to decide on your premiums."

It added: "The device records a car's speed, the distance it travels, how it accelerates and brakes, and what time of the day or night the car is used. All this information builds a profile of the driver that the insurance company uses to work out how much of a risk they are to insure. The safer a driver you are, the less you'll have to pay for your policy. But, on the other hand, if it seems that you drive erratically or riskily, your premiums can go up."