Would GDP fall if HMS Queen Elizabeth sinks?

I’m always on the lookout for GDP stories – what is GDP, how is it measured, and what are the problems of using GDP to measure social progress, standard of living and sustainability.Big changes coming to the national accounts next month, which means that GDP will be calculated slightly differently.

According to the BBC, one of the changes is to the treatment of "military weapons of destruction and the equipment needed to deliver them". In the past, government spending on weapons was considered to be just consumption by governments - from next month some of it will count as an investment.

That increased government “investment” in things like ships, aircraft and tanks will add £3.5bn to GDP for 2009. The recently named HMS Queen Elizabeth aircraft carrier is expected to cost about £6.2bn. So if it were sunk, would that knock 1.6% off that quarter's GDP?

According to the specialists at the Office for National Statistics (ONS) the answer is uncertain. Most military equipment will be written off gradually over a theoretical 20-year lifespan. But they say that if the loss were really big (like the loss of an aircraft carrier) they might have to adjust the model to take that into account, which would mean there would be a big hit to GDP.