For eighteen years he has been the silent shadow in every photograph, the little boy in dinosaur pyjamas standing next to the empty swing where his big sister used to play. Yesterday, on the exact anniversary of the night Madeleine vanished, Sean McCann (now 20) ended nearly two decades of silence with a 42-minute video posted to an anonymous YouTube channel that has already been watched more than 37 million times.

The title is only four words long, but it has detonated across the world:

“My Mum Killed Maddie.”

In a calm, measured voice that still carries a faint trace of Merseyside, Sean sits in front of a plain white wall wearing a black hoodie and no jewellery. There is no music, no cuts, no tears until the final thirty seconds. What there is, instead, is a detailed, devastating timeline of the evening of 3 May 2007, told for the first time by the only other child who was in apartment 5A that night.

“People think I don’t remember because I was two and a half,” he begins. “But trauma burns things into you. I remember every second.”

According to Sean, the official Tapas 7 “checking” story is a lie the parents rehearsed with police within hours.

“I woke up crying around 8:45 p.m. because I’d wet the bed. Maddie came into my room; she was already awake reading her Cat in the Hat book with a little torch. She helped me change my pyjama bottoms. That’s why the bed was turned down when police arrived later; she was trying to help me hide it so I wouldn’t get in trouble.

“Mum came in once, at about 9:05. She was tipsy, laughing, smelling of wine. She told Maddie to go back to her own bed and me to go to sleep. Then she went back to the restaurant. She never checked again. Not once.

“The patio door was left unlocked. The shutters were up. Maddie told me she was scared because she could hear ‘monster noises’ from the road. I fell asleep again. When I woke up the second time, probably around 10, Maddie was gone. The front door was wide open and the flat was cold. I stood in the hallway calling her name. Nobody came for a very long time.”

Sean claims Kate McCann did not discover Madeleine missing until 10:03 p.m. (“I know because I could see the oven clock from the hallway”). He says his mother’s scream was not shock; it was panic that the checking story had collapsed.

“She ran straight past me to the Tapas restaurant shouting ‘Madeleine’s gone!’ but she already knew the timeline didn’t add up. That’s when they all started rewriting it. Dad told me to stay on the sofa and not talk to anyone. I heard him on the phone saying, ‘Tell them we were checking every half hour.’ I was two, but I understood they were lying.”

The most chilling section comes at the 28-minute mark.

“I blame my mother,” he says, voice finally cracking. “Not for taking her eyes off us for a second; for leaving us alone night after night while they drank two bottles of wine each with their friends. Maddie was three. I was two. The window was open. Anyone could walk in. She chose Sauvignon Blanc over sitting with her babies. That choice destroyed our family.”

He goes on to accuse Kate and Gerry McCann of using the Find Madeleine fund to “buy silence”; including, he claims, paying for private schooling for him and his twin sister Amelie on the condition they never speak publicly.

“I’ve been told since I was five that if I ever said the wrong thing, the money would stop and we’d be taken into care. Today I’m 20. I don’t need their money anymore.”

Sean ends the video with a direct message to his parents:

“You turned my sister into a brand and me into a ghost. You cashed in on her bedtime photo while I was having nightmares in the next room. I don’t know if Maddie is alive or dead. But I know this: she was alive when you left her, and she was gone when you came back. That’s on you. Both of you.”

Within hours the video was removed “for violating community guidelines”, only to be re-uploaded to multiple platforms. Portuguese police have confirmed they are “aware” of the footage and are “assessing its evidential value”. The McCann spokesperson called it “the desperate work of online trolls exploiting a vulnerable young man” and announced Kate and Gerry will not be commenting “out of respect for their children”.

But the damage is done.

#SeanSpeaks is the number-one trending topic worldwide. Old footage of Kate McCann’s 2007 press conferences is being shared alongside clips of Sean’s video, with thousands pointing out the identical cadence in their speech (“She’s saying the same rehearsed lines he says they forced on him”).

For eighteen years the world asked, “Who took Madeleine?”

Last night her own brother answered:

“Nobody took her. They left the door open, and she paid the price.”

Whether Sean’s account reopens the official investigation or simply breaks what remains of a shattered family, one thing is certain: the little boy in the dinosaur pyjamas just made sure the world will never look at that holiday photo the same way again.