The UK government set out its strategy to get the country to “net zero” – where greenhouse gas emissions are reduced to a minimum and are offset by other measures – by 2050 this week.

The plan involves “leveraging up to £90 billion of private investment by 2030”.

In an interview with BBC Radio 4 yesterday, the business secretary Kwasi Kwarteng was challenged to provide evidence for this figure, which journalist Amol Rajan suggested was a “heroic scenario”.

In his reply, the Spelthorne MP said: “We’ve already seen £100bn in the last nine years deployed in offshore wind in one particular renewables sector. So it’s not a heroic assumption to say that by 2030 we will have attracted an additional £90bn, which of course is less, you will notice, than the £100bn that we’ve stimulated in offshore wind investment.”

But when we asked the Department for Business, Energy and Industrial Strategy (BEIS) to provide a source for the £100bn claim, they told us the real figure was “around £47 billion”.

The stat – which is relayed in the government’s own Net Zero Strategy document – comes from Wind Europe, a Brussels-based trade body representing the wind energy sector.

The report the Department showed us reveals that, while the UK has been “the biggest offshore wind market for capital spending commitments over the last ten years”, the investment we’ve attracted in that time totals 56bn euros (roughly £47bn, as the Department said).

It seems the £100bn figure refers to offshore wind investment since 2010 across all of Europe, of which the UK attracted about half.