THOUSANDS of screws used to secure the decking on Weston-super-Mare's new £51 million Grand Pier may have to be taken up and replaced – because they are the wrong size.

It is understood that the error was discovered during an inspection of the new decking, which was laid around the pavilion last month.

Engineers said the screws used to pin the decking into place are not of the right specification and around 40,000 of them could have to be taken out.

The mistake came to light after an inspection of the decking was carried out when it was revealed the wooden planks were already failing and concerns had been raised about its structural integrity. Structural engineers have been brought in to assess the problem and are preparing a report on the decking.

It is understood that although the decking will be able to take the weight of pedestrians, there are concerns about whether it will be able to safely take the weight of heavy vehicles.

Main contractors John Sisk and Son is waiting to see the result of the report before making a decision about whether the screws need to be replaced.

Work to rebuild the Grand Pier started in April 2009 but the project is two months behind schedule after being hit by a number of delays.

John Sisk and Son was due to hand over the landmark to owners Kerry and Michelle Michael at the end of June so they could start the fit-out of the pavilion.

But because of delays with the project, the handover never happened.

The news will come as another blow to the Michaels who estimate they are losing a million a month in revenue during the peak summer months because the pier is closed.

Mr Michael refused to comment on the screw size being wrong, but has previously said: "Structural engineers are looking into the design of decking to see if it meets the requirements and if, as I fear, it does not, it will have to be stripped and re-done.

"I am bitterly disappointed at the continued delays on the project."

This is the latest in a series of major blows to the project to rebuild the pier, which was destroyed in a fire in July 2008.

The Evening Post exclusively revealed last month that one of the main subcontractors working on the project had gone bust.

Bristol-based heating and design engineering firm Joyner Morgan, which was the main mechanical services contractor on the pier working for John Sisk and Son, went into voluntary liquidation.

As a result of the delays, the Michaels have been forced to cancel all bookings up until September 10, including children's and engagement parties.

They have also recruited around 300 people to work on the attraction either full time or part time – the majority of whom are still waiting to start their new jobs.

But as some of the jobs were just for the summer, some of those recruited will not get to realise their dream of working on the landmark.

Although a completion date has yet to be announced, the Michaels believe it is "imminent".

No one at John Sisk and Son was prepared to comment on whether the wrong screws had been used when laying the decking, but admitted the entire project was a complex one.

A spokesman for John Sisk and Son said: "We are continuing to work in close partnership with Grand Pier Limited in order to achieve the completion and reopening of the pier as soon as possible.

"Sisk has been working with Grand Pier Limited to meet the scheme's evolving requirements and address the challenges of an extremely complex project – including addressing the issues over the decking design that have emerged recently. Unfortunately, despite our combined best efforts, this has led to delays to the opening.

"We continue to work around the clock to complete the works to return this landmark of Weston-super-Mare back to its rightful iconic place at the heart of the community."