A man leapt to safety moments before the 90-tonne crane he was driving plunged into a canal as a towpath collapsed under its weight.
The driver escaped without injury as the crane flipped onto its roof and became submerged in the Leeds & Liverpool Canal after the ground crumbled beneath it at Dobson Locks in Apperley Bridge on Friday morning.
The Canal & Rivers Trust, which was carrying out preparation work to replace the lock gates, said an investigation had been launched into why the towpath gave way in what it has described as a “rare incident”.
Workers in fluorescent jackets could be seen at the site where the crane was on its roof under the water, with its wheels in the air.
Bungs were placed around the crane to prevent any fuel from the vehicle spreading along the waterway.
Graeme Atkins, 53, of Idle, told how he saw the submerged crane, with its windscreen wipers still going, as he walked his two dogs along the towpath at around 8.30am.
“I couldn’t believe it, it’s not something you see every day,” he said. “It’s a really unusual sight. The workers were just stood there looking at it, I think they were stunned.
“You can see where the towpath has crumbled. It’s extremely lucky no one was hurt.”
Mr Aktins, a former Premier League referee, said preparation for the lock replacement had been taking place over the last three weeks, with a road being built across land at Bottom Farm for access to the towpath.
“They had been pruning trees back and tying overhead cables to make it safe for access. Then the first day the crane goes onto the site this happens,” he said.
“I don’t know how they’re going to get the crane out, but I imagine it will take a while.”
Part of the towpath has been fenced off until the crane is removed from site, but it is not yet known when this will happen.
The crane is designed to lift 90 tonnes, although it weighs around 64 tonnes.
Vince Moran, operations director at the Canal & River Trust, said: “First and foremost, I am thankful that the driver or anyone nearby wasn’t injured.
“When planning and undertaking heritage repairs to any of our waterways we take steps to ensure that they meet stringent safety measures.
“Of course we need to understand why this particular patch of towpath gave way and will urgently review the circumstances behind this rare incident and apply any lessons learned from it.”
The Health and Safety Executive has been informed about the incident.