Open borders or fair wages: the left needs to make up its mind | Paul Ormerod

Mass immigration has boosted Britain's economy but cut the earning power of those at the bottom

Mass immigration increases inequality. This is the unpalatable fact the liberal left in Britain refuses to accept. Markets are imperfect instruments. But it is not necessary to subscribe to free market economic theory to believe that large increases in supply tend to drive down the price. And the price of labour is the wage.

Last Friday, the Guardian front page carried a report from the Office for Budget Responsibility, claiming that higher net immigration increased the UK's economic growth rate. According to the mainstream theory of economic growth, this is undoubtedly true. Higher growth can be created by sustained increases of either capital or labour.

Related: Immigration: let's change the way we talk about it | Jonathan Freedland

A modern economy relies on innovation. This should be the focus of policy