An investigation into the grounding of a ferry has revealed serious concerns about the safety of the service.

The Marine Accident Investigation Branch has criticised the way the French-owned port of Newhaven and carrier Transmanche Ferries operate.

There have been 13 incidents including groundings, near groundings and collisions involving the MV Dieppe and the Sardinia Vera in the last four years.

The agency is insisting a risk assessment is made to assess the suitability of both vessels to operate from Newhaven.

Transmanche plans to introduce two new 16,000 tonne ferries to the route but they will not be ready for up to 18 months.

The report says: "Of specific concern is that the suitability of MV Dieppe to safely operate a scheduled service out of Newhaven is questionable."

The report states that it took three accidents at Newhaven involving the 17,500-tonne MV Dieppe in 22 months for restictions to be placed on the way the ferry sailed in and out of the port.

The report says the vessel may be too big to operate from the port and its manoeuvres in high cross winds are "hazardous".

Even the main tug at Newhaven, the Nore Commodore, has difficulty in assisting MV Dieppe and has been ineffective in freeing both vessels when stuck outside the harbour on sandbanks.

On most occasions they have had to wait for the tide to rise.

The investigation was launched after the 12,000-tonne Sardinia Vera ran aground at Newhaven on January 11 and was stuck on a sandbank for two hours while attempts were made to refloat the vessel which was carrying 47 passengers, 53 crew members and 47 container lorries.

It was found bad weather led to an increase in silting, which had not been detected because of defective surveying equipment, and there was a lack of suitable fixed navigational aids.

Investigators have questioned whether Newhaven Port and Properties Ltd, which is owned by the French Conseil General de Seine Maritime, has the ability to maintain safety at the port.

The report says: "The investigation found that Newhaven Ports and Properties was apparently unable or unwilling to ensure an adequate level of safety was maintained as it pertained to the Transmanche Ferry operation in the port.

"There was no evidence of an effective dialogue between Transmanche Ferries, the ship's managers and Newhaven Port and Properties to assess the risks associated with operating a scheduled service of large ferries from the port.

"As a consequence, safe operating criteria has been defined piecemeal over the years, often following accidents and incidents."

It said proper risk assessments should have been made before introducing large vessels on to the route from 2001. Better staff training and monitoring of safety management procedures is also recommended.

Steve Forrest, operations manager for Transmanche at Newhaven, said: "We have already implemented many of the suggestions and both our ships are fit to sail."