Official report on sinkhole by the Victoria Fountain in Brighton

But the fountain – and the Victorian sewers below – do not seem to be in further danger and steps can be taken to spread loads in future to prevent a recurrence.

The weight of the ride, supported by a jack, appears to have damaged a thin surface area which had a void or cavity beneath it, caused by water washing away fine soil.

The official report was prepared by civil and structural engineer Jon Orrell, a founder partner of the Hemsley Orrell Partnership (HOP), for Brighton and Hove City Council.

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Mr Orrell said: “From our surface visible observations, it would appear that a high load from a jack has ‘punched through’ surface layers in an area where a void probably already existed below.

“The load imposed by that jack, locally, was far greater than any general use would have generated before.

“Provided any exceptional future points loads, such as heavy lorry wheels or stabilising jacks, are appropriately dealt with by means of suitably sized spreaders – and the situation properly monitored – then we do not believe there is cause for immediate concern in respect of additional swallow holes appearing.”

The sinkhole, in Old Steine Gardens, appeared after the Christmas market ended last December and is not linked to problems with the Victoria Fountain which is temporarily propped.

The report looked at a number of issues with the fountain

The fountain’s problems were down to corroding bolts and “faulty services above ground” – not voids beneath the surface or other geological issues, according to a covering report to councillors.

HOP has been appointed to give specialist advice and manage a £250,000 project to repair and renovate the Victoria Fountain.

A report to the council’s environment, transport and sustainability committee said: “These works are now programmed to start in 2023 following two unsuccessful attempts at tendering the contract whereby no tender returns were received.

“It is part of HOP’s brief to assess the ground conditions to ensure safe working practices including the use of a crane that will be needed for the fountain refurbishment project.

“Difficulties have been experienced in tendering this project against the background of nationally spiralling construction costs and lack of construction specialisms and skills.

“We have had two unsuccessful tendering attempts. Both were via the council’s existing frameworks agreements and a specific list of contractors recommended by the external structural consultant.

The sinkhole appeared following the last Christmas market

“A total of 12 contractors have been invited to tender and zero responses have been received.

“A third tendering exercise has finished and two tender returns have been received which are currently being analysed.

“The intention is to appoint the successful contractor in late November, aiming for a start on site mid-December and a completion of the refurbishment project by the end of March.

“However, this will be dependent on the confirmation of the costs and funding, with the timeline being dependent on weather conditions and the volume of ‘unknowns’ – as until we crane the upper parts of the structure out, we will not know the full extent of the condition and deterioration of the cast iron structure and the mechanical services.”

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The report was prepared in response to a motion proposed by Conservative councillor Mary Mears at a meeting of the full council in February.

It was listed for debate at the environment, transport and sustainability committee at hove town hall last night but – four hours into the meeting – it was noted without discussion.