Having added "omni­shambles" to the Oxford English Dictionary this week, lexicographers may have been looking for a handy example.

They need not look further than the UK Government's catastrophic handling of the procurement of two new Queen Elizabeth Class aircraft carriers for the Royal Navy.

Today's report by the Westminster Public Accounts Committee recounts the sorry saga.

The last Labour Government commissioned the warships and the planes they would house, jump-jet versions of the US built F-35 strike fighter. But soon after taking power in 2010 then Defence Secretary Liam Fox made great play of reversing this "error" and announced at least one of the new carriers would be equipped to take the F-35C carrier version of the aircraft, requiring launch catapults to be retro-fitted to the ship.

In 2012 Dr Fox's successor Philip Hammond embarrassingly reversed the decision again when it turned out it could cost up to £2bn extra, leaving one ship mothballed and the other aircraft carrier effectively unusable until 2023, instead of 2020 as planned.

Mr Hammond's call, we now know cost taxpayers at least £74m.

Today's is a devastating report, from a committee which comprises 14 MPs, including eight Conservatives and one Liberal Democrat.

It points out that the 2010 decision was based on deeply flawed information, generated under time pressure and in secret. In managing what has become the UK's largest engineering project - now based at Rosyth - and one of its biggest procurement decisions, the MoD made unbelievable errors, including forgetting to factor in costs such as VAT and inflation, the committee says.

More worryingly, the MoD has even now been unable to convince MPs on the public accounts committee that it has the programme under control. There is potential for further uncontrolled growth in costs.

The prescriptions from the committee are sensible. The MoD has argued that changes to the carrier building programme have come about as it altered its view about working with allies and the urgency with which new carrier capacity is needed. "We kept changing our minds," is an alarming excuse, as MPs point out. They are right to demand that the department does everything it can to decide what it needs and stick to that decision over time. Decision makers need early information, transparent requirements and the freedom to make choices without political interference.

Finally, despite having 400 people working on the Carrier Strike programme, the department lacks the procurement skills to manage risks, the report says. Essentially, industry has the UK Government over a barrel, with a contract which leaves risks with taxpayers, not contractors.

Omnishambles, a word borrowed from TV political satire, has entered the language because it identifies something real. But when the costs are real and so high, incompetence ceases to be funny. The Government must adopt the report's proposals to bring this project under control, proposals which are themselves little more than the definition of common sense.