Footage posted online shows waves pounding the historic structure before part of it falls into the sea.
It comes amid a yellow weather warning for wind along the Sussex coast as a result of Storm Austen – the first named storm of the year.
First opened in 1866, it was the first pier in England to secure Grade I listed status.
But safety concerns and financial difficulties led to the West Pier’s eventual closure in 1975.
Since then, the structure has declined and experienced other partial collapses due to extreme weather.
In 2003, two separate fires – both suspected to be arson – significantly damaging the pier, leading English Heritage to declare it “beyond repair”.
Professor Fred Gray, honorary historian at the West Pier Trust, said that pier has continually been ‘whittled away by nature’ ever since the fires of 2003.
He said: “All ruins are alive and ever-changing, and this is true of the West Pier. It is far too dangerous (and costly) to try to stabilise the structure.
“Everyone interested in the pier should stay at a safe distance and watch the battle between pier and the elements. We don’t know when the pier will eventually disappear beneath the waves, but disappear it will.
“That so much still remains is a tribute to the Victorian designers and engineers who built the pier.”

5. Part of historic Sussex pier collapses during Storm Austen
Storm Austen - West Pier Partial Collapse 23/10/26. Photo: EDDIE MITCHELL

6. Part of historic Sussex pier collapses during Storm Austen
Storm Austen - West Pier Partial Collapse 23/10/26. Photo: EDDIE MITCHELL

7. Part of historic Sussex pier collapses during Storm Austen
Storm Austen - West Pier Partial Collapse 23/10/26. Photo: EDDIE MITCHELL

8. Part of historic Sussex pier collapses during Storm Austen
Storm Austen - West Pier Partial Collapse 23/10/26. Photo: EDDIE MITCHELL

