Police have been scouring London for explosives and hidden weapons in the run-up to the royal wedding.
Officers inspected drains, lamp-posts and traffic lights in Westminster to ensure Prince William and Kate Middleton's big day is trouble-free.
They looked under manhole covers and broke security seals on the Mall, looking for any suspicious items, an operation that will continue until the big day.
The Metropolitan Police are guarding against any terrorist threat and it is thought that William and Kate's happy day will be a prime target, with the Royal Family, senior members of the Government, big-name celebrities and 50 foreign heads of state attending.
With a worldwide television audience of up to two billion, senior officers will want to avoid an incident like the attack on the Prince of Wales and Duchess of Cornwall's Rolls-Royce during the tuition fees protests last year.
Inspector Ian Fairman, in charge of the search teams, said: "Officers are trained to be vigilant and check areas where items may have been hidden.
"Officers will be checking vulnerable areas all along the route of the procession."
The couple - William accompanied by his brother, Prince Harry, and Miss Middleton by her father, Michael - will leave from Buckingham Palace and travel in cars down the Mall before returning in a procession following the ceremony in Westminster Abbey.
The Royal Family, best man, maid of honour, bridesmaids and the Middletons will all be part of the parade, and the Metropolitan Police expect the road to be lined with thousands of well-wishers.