Here are some Tories:

Once they enter the workplace, the British are among the worst idlers in the world...We work among the lowest hours, we retire early and our productivity is poor.

This is silly. We must not equate being idle in the sense of putting in few hours with being idle in the sense of having low productivity in those hours we do work. They are not just different things, but opposed things.

Let's look at the facts.UK workers do indeed put in fewer hours than most. OECD data show that the British worked an average of 1625 hours in 2011. That's less than the OECD average*.

But it's not the case that our productivity - in terms of output per hour - is poor.In fact, it's above the OECD average.

What's more, across the 35 countries in the OECD's sample, there's a strong negative correlation (-0.81) between hours worked and productivity.Nations with long working hours tend to have low productivity, and nations with shorter hours have higher productivity.

Of the 11 OECD countries with the longest working hours, all have lower productivity than the UK - in most cases very much so. Koreans, for example, work one-third longer than we do, but those hours are only 40% as productive.

By contrast, every single one of the nations with shorter hours than the UK has higher hourly productivity.

The US is an outlier by international standards in having both long working hours and high productivity.

There are good reasons for this strong inverse correlation:

- Poor countries tend to have low capital stocks. They therefore need higher labour inputs.

- Poor countries have less chance to specialise properly, because as Adam Smith said, the division of labour is limited by the extent of the market. This too reduces productivity.

- There are diminishing returns to labour. If you work long hours, you'll be unable to concentrate and so you'll be less able to fill the unfogiving minute with 60 seconds of distance run. Instead, you'll stop for breaks. There's a reason why "watercooler talk" is an American expression, not a Dutch one.

- Leisure is a normal good. As our incomes rise, our demand for it falls. You'd expect richer folk to work less, on average.

But what if we compare the UK to those nations with both higher hourly productivity and higher working hours than us: Sweden, the US, Finland, Spain, and Australia? Can we blame the UK's low productivity relative to these upon our laziness?

Not necessarily. There are countless other possibilities, such as bad planning laws, poor management (pdf), a lower capital stock (pdf), less product market competition, a worse cyclical downturn, and so on. Blaming lazy workers is, well, just lazy.