A mobile bank introduced to the Isle of Barra will cost RBS around £2,000, with critics saying it demolishes arguments that the island's branch closure would be cut costs.

RBS has recently come under under fire for its sweeping branch-closure programme taking place this year with some 62 set to be affected.

Among those up for closure was Barra’s only branch in the island’s main village of Castlebay.

It has since been given a reprieve until the end of the year, when it will be up for review.

The tiny Hebridean isle is home to around 1,100 people and after the branch’s closure, they would be dependent on a mobile banking service with the next nearest branch a ferry ride and 27 miles away on a neighbouring island.

However Western Isles MP Angus MacNeil said that shutting the island’s branch and replacing it with a mobile banking service would not be as cost effective as RBS have been insisting.

Mr MacNeil, who lives on Barra, said that RBS would spend more than £2,000 a month on travel costs if it proceeds with the closure.

The mobile bank is due to visit the island three times a week at a cost of more than £200 a return ferry trip, together with staff costs and any unforeseen travel disruptions.

He said: “Closing branches is supposed to be a money saving exercise but in the case of the island branches, the costs involved in a mobile banking service might prove otherwise.

“When RBS add up all the travel costs and the additional unexpected costs that can incur if there is travel disruption, they should think again.

“One department of RBS is pulling the wool over the eyes of another department if they’re selling the closure of the Castlebay branch as a saving.

“I hope that the independent reviewer will also look at this issue, and the fact that the RBS van will put further pressure on an already busy ferry service.

“The local community are telling RBS to drop their plans; the Scottish Affairs Committee are telling RBS to drop their plans; and now their own bank balance might tell them to drop their plans for Castlebay and Lochboisdale too.”

His move comes as RBS recently defended its closure of 52 Scottish branches this Spring, saying it was a necessary response to the challenges posed by dramatic changes in consumer behaviour.

Originally 62 across Scotland were due to close, how 10 branches are to remain open until at least the end of 2018 as part of a full independent review.

If the bank finds that there is greater usage of a branch, its future will be subject of a further review.

Alongside Castlebay, branches under consideration are Biggar, Beauly, Comrie, Douglas in Lanarkshire, Gretna, Inveraray, Melrose, Kyle and Tongue.

Speaking at the bank’s general meeting in Edinburgh, Chief Executive Ross McEwan said that he had personally reviewed all the proposed branch closures and thought about the “the ramifications on vulnerable customers”.

He said that mobile branches operated by the taxpayer-backed lender call at 440 places in Scotland, while customers can complete tasks such as paying in cash and cheques at 1400 post offices.

The closures would leave the country with less than 100 branches.

His comments came as RBS reported a profit of £792m for the first three months of the year, up from £259m for the same quarter last year.

Mr MacNeil has remained vocal in his criticism of RBS following their original decision to close the branch in Castlebay and reduce the opening hours of the Lochboisdale branch on neighbouring South Uist.

He says that Barra’s branch is better used than the RBS claim.

The island’s only ATM - attached to the bank in Castlebay - was also saved after a U-turn by RBS.

Meanwhile an online petition urging RBS to reconsider closing the branch has topped over 11,700 signatures - more than ten times the isle’s population and signed by many non-islanders.