A section of the historic Clacton pier has collapsed into the sea during structural refurbishment work.
Passers-by snapped photos of the damaged pier, which dates back to 1871 and is a key attraction in the seaside town, after part of the structure fell into the North Sea this morning.
A small section of the outside ride deck collapsed while concrete was being poured ahead of the installation of a new rollercoaster, at an area which was already closed off to the public.
The pier said its aim was to ensure that the wet concrete being laid would not result in undue structural movement to the existing concrete deck.
Pier director Billy Ball said that as this was taking place, excess vertical movement of the piles caused four bays of the existing slab to fail.
"This was being carried out under controlled conditions at a time when the tide was up and no one was under the pier," he said.
"Site personnel were carefully monitoring the pouring of the concrete when the collapse happened, and everyone was evacuated from that particular area which is now fenced off."
Mr Ball added that similar tried and tested methods have taken place in other areas of the pier over the past 10 years that it has been in his family's ownership.
So far around 4,000 square metres of such work has been carried out and this area involves 140 square metres.
"As part of our ongoing commitment to ensure the pier remains safe and serviceable, we go to extensive lengths to analyse and calculate the integrity of the existing structure before constructing any new attractions," he said.
"Our structural engineers are currently assessing the situation."
The collapsed section of the ride deck is the part which had been set aside for the new Looping Star ride due to open in the spring - but now there are concerns this could be delayed.
Nigel Brown, communications manager for Clacton Pier said: "The collapse is most likely going to impact on the timetable for opening the Looping Star but it is too early to say by how much.
"The pier remains open now and we are still expecting a limited number of rides to open on Monday."
Alex Porter, cabinet member for leisure and tourism, said the pier is a key attraction in the seaside town.
"The pier brings a lot of people into Clacton," he said.
"Tourism is a massive part of our economy here, so the pier is a really important place for visitors and also its employees."
Mr Porter said that when he heard the news of the collapse he visited the pier and was glad to find the damage was "only minor".
He said: "It was just to do with improving the pier, it wasn't a failure. Sadly these things happen sometimes.
"The pier is happy that everything is safe to stay open which is great news."
The pier was set to open its rides tomorrow, however it announced on Thursday that this would not be happening due to Storm Dennis.
The damaged area of the pier will be entirely fenced off to the public when the rides reopen.
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