LONDON - The first of four British military tankers being built in South Korea to support operation of the Royal Navy's new aircraft carrier force has finally been handed over to the Ministry of Defence, twelve months later than expected.

"Royal Fleet Auxiliary Tidespring was accepted off contract earlier this month and is due to arrive in the UK in 2017 for customisation and capability assessment trials before entering service," an MoD spokesman confirmed to Defense News Jan 17.

RFA Tidespring should have been accepted off contract last January but has been delayed while technical issues have been resolved by the builders, Daewoo Shipbuilding and Marine Engineering (DSME).

"Some technical issues were discovered following RFA Tidespring's sea trials, and alongside this, new regulations around cable insulation required adjustments to the build schedule. These issues were fully resolved prior to acceptance," said the spokesman.

The 37,000 tonne tanker was due to have been in service with the RFA, the logistics and operational support arm for the Royal Navy, last September to start replacing single-hulled ships that no longer meet international standards.

Under the original time frame three of the four ships should have been handed over to the British by now with the final tanker scheduled to be accepted this April.

Despite the problems, the spokesman said all four ships are "expected to be in service by the end of 2018, consistent with the original intent."

The spokesman said the firm-price nature of the contract meant the delays had not resulted in any additional cost to the MoD.

The ships are the first element of an overdue modernization of the Royal Fleet Auxiliary meant in part to support the introduction of the Royal Navy's new 70,000-ton Queen Elizabeth class aircraft carriers.

The first of two carriers is due to start sea trials in the next few months.

Britain ordered four tankers from DSME in 2012 in a $597 million deal that sparked controversy here over the MoD's decision to put the program out to international competition, rather than reserving the work for local yards. None of the British yards submitted a bid.

On its arrival in the UK the tanker will be delivered to the A&P yard at Falmouth, western England, for customization work involving the fitting of sensitive equipment like self-defense weapons, ballistic protection and communications systems.

The first tanker is likely to enter service toward the end of the year.

In a statement issued at the start of the month on upcoming developments for the Royal Navy in 2017 Defense Secretary Sir Michael Fallon said Tidespring would "arrive from South Korea in the spring."

Designed by Britain's BMT Defence Services, the new tankers are equipped with a helicopter flight deck and hangar.

Besides ship and aviation fuel, they are designed to hold ammunition and solid stores.

The handover of the first tanker will ease embarrassment in the MoD over the delays by a foreign contractor just at the time the British start to gear up for a competition to build three fleet-support ships capable of delivering munitions and stores to the carrier task force.

An MoD spokesman said that the new requirement will also be put out to international bids.

"We plan to procure three Fleet Solid Support Ships, as announced in the Strategic Defence and Security Review of 2015, through open competition among UK and international bidders. The programme is currently in its assessment phase, and we anticipate that the MoD will be in a position to award the contract by 2020,"  the spokesman said.

"The current planning assumption is that ships [will enter service] from the mid-2020s . . . to replace aging Fort-class vessels," he added.

Andrew Chuter is the United Kingdom correspondent for Defense News.

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