Cllr Linda Wild was dismayed that the century-old bridge had stuck, trapping a charter boat bound for Scotland in the upper harbour, despite assurances from North Yorkshire County Council's Highways chiefs that the problems which beset the historic structure throughout the summer had been solved.
Cllr Wild said: "The swing bridge is broken and will not open.
"They can’t repair it until Tuesday.
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"It goes to show they haven’t fixed the issue at all; they just got lucky for a few months!
"I feel like we have been patted on the head and fobbed off in the hope that we would stop making a fuss.
"With less than a week to Christmas, here we are again - the town is split in two and the harbour is paralysed.
"It's effectively delaying Christmas for some of the fishing community as they return home this week.
"It's just not acceptable."
Earlier in the year, Whitby borough councillor Phil Trumper called for a replacement bridge fit for the 21st Century after a series of breakdowns.
And he reiterated that when speaking to the Gazette today, saying the bridge is crucial for the connectivity of the town.
"Anything quite large up the harbour cannot get out and is stuck there for the next few days until it's repaired," he said.
"It's not a great advertisement for a modern harbour.
"I think we need to start thinking seriously about a replacement.
"If the bridge is stuck open (while being repaired) then it affects people's shopping and trying to see their families.
"I don't think they realise just how it affects peole - they just see it as a bridge closure."
North Yorkshire County Council's Bridges Manager Philip Richardson said the swing bridge was currently unable to open due to the failure of a valve controlling the bridge speed, but was open to highway traffic.
Mr Richardson said it is the team hoped to put in a temporary fix tomorrow (Dec 21) which would allow boats through.
"We are sourcing a replacement part to carry out a permanent fix and will keep the public updated of our progress," he told the Gazette.
"The swing bridge is serviced regularly and this issue is not related to the mechanical issues we experienced last summer when it was not possible to close the bridge.
"We recognise the importance of the swing bridge to Whitby’s economy.
"We have invested in upgrades and a computer monitoring system so that engineers can see a fault immediately and where possible bring the spares needed for a repair if we do not have them in stock.
"This bridge is sited in an extreme environment and operates everyday on two tides - more than any of the other moving bridges that we maintain and, like all complicated machinery, it will fail from time to time.
"We apologise for the disruption this has caused but every effort is being made to repair the issue as quickly as possible."