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The last-minute hitch on Prince William and Kate Middleton's wedding day

The couple tied the knot in April 2011

Ainhoa Barcelona

Months and months of detailed planning went into the Duke and Duchess of Cambridge's 2011 royal wedding, but in ITV documentary The Day Will and Kate Got Married, a former Metropolitan Police commander revealed how Scotland Yard faced a worrying situation on the big day.

On the morning of 29 April 2011, William and Kate's nuptials, the police discovered a suspicious car parked outside The Goring hotel in London where the bride was staying.

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Thankfully, nothing came of it, but there were moments of crisis at the police headquarters as explosions officers tried to investigate if there was a hidden bomb in the vehicle.

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"We had a secure zone around The Goring hotel," former Metropolitan Police commander Bob Broadhurst said in the documentary, adding that the police had arrested 20 people, who they deemed "known anarchists", in the lead-up to the royal wedding.

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"I don't know how it happened and I don't really want to know how it happened to this day, but somebody in a car got through the secure zone, drove up close to The Goring, just around the corner, got out of the car and legged it. And joined the crowd."

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Kate and her party stayed at The Goring the night before the wedding

"Now we have a real problem," he recalled. "This is a potential bomb in the car. It's so close to the entrance and exit to The Goring, that we might not be able to get Kate and her party out on time. It was 15, 20 minutes before her due departure time. You could cut the silence with a knife as we tried to solve the issue."

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The day went off without a hitch

After the initial scare, Bob explained: "Our explosions officers had turned up, it wasn't a bomb, so we were not only able to downgrade the threat, but also stick to plan A. Let's go for it and get her out.

"I think that poor individual, whoever it was, maybe a tourist, came back to find their car with no doors or windows and a parking ticket."

Luckily, William and Kate's big day went off without a hitch. Some 1,900 guests attended the ceremony at Westminster Abbey, after which the Queen hosted a lunchtime reception at her home, Buckingham Palace. Prince Charles also hosted an evening of dinner and dancing at the palace for William and Kate's closest loved ones.

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