The Royal Navy’s new Type 31 frigate programme has been hit by an embarrassing and expensive setback after construction errors forced major rework on the first two ships in the class. Defence contractor Babcock International has confirmed that issues in the build process will require around £140 million of remedial work, pushing cumulative losses on the programme to more than £300 million. The mistake has raised fresh questions about quality control, risk management and value for money in the UK’s naval shipbuilding plans.

The problem centres on HMS Venturer and HMS Active, the first and second Type 31 frigates being assembled at Babcock’s Rosyth yard in Fife. In a trading update, the company said it had experienced “higher‑than‑expected levels of rework as a result of design changes and the long‑term impacts of out‑of‑sequence build activity earlier in the programme”. In practice, this means that some parts of the ships were fitted in the wrong order or to designs that later changed, forcing complex and costly corrections late in the build.finance.

Because much of the rework is happening during the outfitting stage, rather than in earlier, more flexible phases, the impact on time and cost is magnified. Babcock said that while a certain amount of rework is normal on a complex warship project, the level and timing in this case went beyond expectations. The company has now taken a £140 million charge to cover revised costs needed to complete the design and construction of the Type 31 programme, including an estimated £100 million of revenue reversal.

The setback is particularly awkward given wider scrutiny of Royal Navy shipbuilding and past problems on other major vessels. The aircraft carrier HMS Prince of Wales, for example, was sidelined in 2022 by a propeller shaft misalignment measured in fractions of a millimetre, leading to a repair bill estimated at around £25–31 million. In that case, investigators found an installation error on the starboard shaft, underlining how tiny engineering mistakes can translate into huge costs at sea.

For the Type 31 programme, Babcock insists that lessons are being learned and that later ships will not be affected to the same extent. The company says the third and fourth vessels are still in early construction stages and should therefore avoid the worst of the late‑stage rework now required on Venturer and Active. Even so, the extra costs and schedule pressure risk undermining confidence in a programme originally promoted as a relatively low‑cost, exportable frigate design.

The Ministry of Defence will face questions about oversight and contract structures. Complex alliances and supply chains can make it harder to pin down liability and ensure that industrial partners share sufficient risk for errors. At the same time, the Royal Navy needs new frigates in service to replace ageing vessels and meet global commitments, leaving limited room for prolonged delays.

Defence analysts say the Type 31 setbacks highlight the importance of robust design, sequencing and independent checking processes before and during construction. Past cases, such as historic design miscalculations that left some Royal Navy warships dangerously unstable, show how errors that slip through early can haunt a class of ships for decades. The challenge for Babcock and the MoD now is to contain the damage, fix current problems and ensure that future warship projects avoid repeating the same mistakes.