The controversial Ferguson ferry contract which the Scottish Government awarded to the highest of six bidders was based on "incompetence, vested interest or corruption", MSPs have been told.

Ferguson Marine won the contract in 2015 to build two new CalMac ferries despite its £97 million bid being the most expensive, while experts now estimate that it will cost an additional £110 million for the work to be completed.

MSPs carrying out an inquiry into the delayed and over-budget new vessels were told by experts today that the Ferguson ferries appear to be "overspecified" for their purpose.

Alf Baird, a former professor of maritime business at Edinburgh Napier University, said the granted contract was "specifying what is in effect a mini-cruise vessel to run a utilitarian shuttle ferry which is basically a bus".

Liberal Democrat MSP Mike Rumbles questioned why the contract had been awarded to the Ferguson yard, highlighting that it was the “highest price" of all the six yards competing for the job.

Roy Pedersen, a member of the Scottish Government's Ferry Industry Advisory Group, said: "I don't know the answer but three things spring to mind - one is incompetence, the other is vested interest and the other is corruption."

Mr Rumbles accused the SNP Government of pouring taxpayers money “down the drain” by “opting for a company that it was known to be cosy with”.

“It’s also extremely worrying that Transport Scotland felt it necessary to highlight the close relationship between the SNP and the company which ultimately secured this huge government contract,” he said.

“This entire process has been marred by a series of ill-thought through decisions. It’s an outrageous mess. The boats will arrive years late and the public are left paying for yet more mistakes. This government owes taxpayers an explanation.”

Concerns were also raised about the type of fuel to be used by the ships, either diesel or liquefied natural gas (LNG).

MSPs were told LNG would have to come from the south of England, meaning a 1,000-mile trip to the ferry terminal at Uig, in the north of Skye.

Mr Pedersen confirmed: "It is a roughly 1,000-mile round trip from the south of England to Uig to deliver the fuel. That in itself is going to be probably on a diesel lorry."

He said that would "negate the relatively minor advantage" to the environment of using LNG.

Mr Pedersen said: "Why build a ship with a capacity of 1,000 passengers for a route, namely the Uig routes, on which there has never been more than 312 passengers carried on any sailing, and when the average carryings are half that and in the winter time even less than that?"

He suggested work on the vessels should be scrapped and started again from scratch, telling the committee: "It's good business practice when you are on a losing run to cut your losses and start again, same when playing poker. It doesn't do to keep putting good money after bad.”

Meanwhile, representatives from the Western Isles told MSPs about the impact the delay in building the ferries has had on their communities.

Barra resident Eoin MacNeil said: "We've had five occasions where we haven't had a ferry for five days. I came out on the ferry last Friday and we haven't had a ferry since then.

"This time of year the stores are empty, the shops are empty, the medical supplies are drying up."