Eyewitness Theresa Lynn saw the wall collapsed on the South Quay and managed to get a picture of the immediate aftermath.

A woman and her dog walked over the top as the wall collapsed (Image: Theresa Lynn)

She posted the image on her Facebook account around an hour ago show the wall completely collapsed underneath the path that runs above.

Posting the picture she said: “Hayle Harbour collapsed just now, saw it happening and a lady and dog walked over it oblivious to it.”

Elaborating on what had happened she replied to one commentator who asked if the lady was OK saying: “My heart came up in my mouth, she admittedly was near the other wall unaware of the collapse but more came away just minutes before she was over it.”

The picture shows huge boulders and earth falling into the harbour water as well as a metal ladder used for climbing down.

The concrete path above is completely unsupported.

Theresa told the Packet: “I was driving through Hayle just before Philps pasty shop and noticed it had collapsed so pulled into their carpark and whilst there more came down.

"A couple of people near it and one man climbed down onto the old lifeboat to get a look. One lady and dog walked over it near the wall just after the collapse that I saw, she obviously could see nothing wrong from the top.”

However, people have been asked not to climb onto the former lifeboat as she is privately owned and there is a risk of slipping and potential injury.

The Hayle Harbour Master told the Packet that they were in the process of closing off the South Quay to the public and vehicles.

He said it would be closed for some time while they assessed what had happened and carried out repairs.

"We will assess what needs to be done to repair and it could be closed for some time," he said.

"We are probably going to have to lift the concrete pad and once we can find the exact cause of the collapse we can fix it."