But corporate tax rates are very high in the US aren’t they?

The US headline corporate income tax rate is indeed high at 35 per cent.

This is the top of the 34 countries in the OECD’s latest analysis set.

This is significantly higher than the 23.4 per cent rate in Japan, 19 per cent in the UK and the 12.5 per cent in Ireland.

But this doesn’t tell the whole story.

Once various allowances and deductions are factored in, the effective corporate US rate on firms comes down to 18.6 per cent according to the US Congressional Budget Office.

Although still relatively high, in 2012 this was lower than the rates seen in Japan and the UK.

Moreover, many US multinationals legally avoid the domestic US corporate income tax by keeping their profits generated abroad offshore.

The result is that the corporate income tax revenue raised by the US as share of GDP was just 1.9 per cent in 2015.

That’s lower than the 2.3 per cent in the UK, the 4.3 per cent in Japan and the 2.7 percent in ultra-low tax Ireland.

The US share of national income raised from corporate taxes is today considerably lower than in the 1960s and 70s when the US government raised upwards of 2.5 per cent of national income this way.

Donald Trump may have a glimmer of a point if his words are generously construed as meaning that the US’s headline rate of corporate tax is abnormally high relative to peer economies.

But it is misleading to suggest that US firms are currently “over-taxed” in a practical sense.

Indeed, the argument put forward by Trump’s advisers is that by lowering the headline rate US multinationals such as Apple and Microsoft will repatriate offshore cash piles and therefore pay more tax to the US government than they do at present.