Jeremy Corbyn launched Labour local elections campaign today – and got caught up in a row about life expectancy.

The Labour leader said the Conservatives were “running our country down”, saying: “Home ownership, opportunities for our children, wages and conditions at work, the NHS, care for our elderly, and now life expectancy: they’re all going backwards.”

Conservative chairman Patrick McLoughlin questioned the line about life expectancy, saying it was in fact improving and adding: “Labour can’t even get their basic facts right.”

Mr Corbyn hit back, saying: “Whether the Conservative party chair can face the facts or not, life expectancy has actually fallen – by a year for 65-year-old women and 6 months for 65-year-old men – since 2013.”

To FactCheck’s mind, there are really two questions here: is life expectancy really falling? And if so, are the Conservatives to blame?

The analysis

Both Labour and the Tories are drawing on the same set of figures here: a long-running projection of life expectancy called the Continuous Mortality Investigation, published by the the Institute and Faculty of Actuaries (IFA).

This year the IFA revised down its projections for the average age people are likely to reach, a fact Labour have seized on.

But is this the same thing as life expectancy “going backwards”?

It may be that the maths suggests you will now live until, say, 89 rather than 90, but that’s still many more years than previous generations, and the average age is still likely to rise in the future.

The fall in projected life expectancy does not mean that individuals are dying younger – Tim Gordon

Tim Gordon, chair of the CMI Mortality Projections Committee, told us: “The fall in projected life expectancy does not mean that individuals are dying younger.

“The latest CMI Mortality Projections Model – with typical inputs – projects that mortality will continue to improve and individuals will continue to live longer.”

It’s a bit like economists predicting lower growth than expected – it doesn’t mean the economy is shrinking, just that the projections are less optimistic than before.

Mr Corbyn made no mention of this and his statements that life expectancy is “falling” or “going backwards” are arguably misleading.

Why have the actuaries revised their projections down?

One factor is that official population data from the Office for National Statistics shows mortality rates are not improving as quickly as they did in the first decade of this century.

Mortality rates improved by more than 2 per cent a year for both men and women between 2000 and 2011 but “since then, annual improvements have been close to zero” (here – Public executive summary for Working Paper 97)

Mr Corbyn obviously blames this on Conservative policies, but is it fair to blame the government for changes in mortality rates after 2011?

There’s no real answer from the IFA on this, as their research does not speculate about causes of mortality trends.

Mr Gordon told us: “This issue is not addressed by the CMI Working Paper.

“As a general comment, mortality is impacted by changes in individual behaviour, lifestyle, health and welfare policy, medical and technological developments and other factors.

“Attribution to specific causes is typically only speculative rather than definitive.”

Labour would probably want to seize on the words “health and welfare policy” here, but the IFA are strictly avoiding coming down in favour of any one cause.

Mr Gordon did make the point that the “exceptionally high rate of improvement observed in the first decade of this century” has also fallen in other Western countries.

The verdict

You are still likely to live longer than your parents, and your children will probably reach an older age than you.

So when Jeremy Corbyn states simply that “life expectancy” is “going backwards”, that’s an oversimplification.

The data source he quotes suggests that life expectancy will continue to rise, but more slowly than expected.

We can speculate about the reasons why improvements to mortality rates have slowed since 2011, but there’s no evidence in this data that Conservative policies are to blame.