Tim Palmer (Letters 6 March) criticises the Echo article assessing the impact of Brexit (2 March) saying both sides of a debate are required for a credible argument or it will been seen as one sided.

This is true except there are often sides in a debate that lack credibility.

Tim Palmer suggested the benefits of Brexit were shown by there being more investment coming into Britain than leaving Britain.

I do not see this as true.

The net inward and outward foreign direct investment is a poor measure of a country's economic position.

Post-referendum inward FDI has indeed been boosted while outward FDI declined, even turning negative in 2019.

However FDI is a measure of UK businesses being bought and sold by foreigners and foreign businesses by Brits.

It measures mainly the change in ownership.

More useful for judging an economy is the level of business investment.

Post-referendum, that measure doesn't show any Brexit boost.

Instead it shows the opposite.

UK business investment rose just 1% through the three post-referendum years while rising 22% through the three preceding years.

Given we are told Brexit is such a golden opportunity, it is strange the Brexit uncertainty has had such a negative effect on business investment.

Dr Martin Rodger

Parkstone