Mass immigration has cut the pay of some skilled British workers by almost £450 a year, a report says today.

Electricians, plumbers and bricklayers are among those whose wages are on average 2.1 per cent lower – £8.40 a week, or £436.80 a year, the Resolution Foundation think-tank claims.

Net immigration – the difference between those arriving in the UK and those leaving – is running at more than 300,000 a year.

Electricians, plumbers and bricklayers are among those whose wages are on average 2.1 per cent lower

Former prime minister David Cameron had promised to reduce it to the ‘tens of thousands’ at the last election.

In a report, the Resolution Foundation revealed the impact that migration has had in some communities.

It said that the proportion of migrants living in some English towns had increased by almost 400 per cent in barely a decade.

Researchers said that, on average, the huge numbers of Eastern Europeans who arrived during that time were paid £3 an hour less than British workers.

However, it said that while wages might rise by £150 if net migration was cut to the tens of thousands following Brexit, the extra earnings could be cancelled out by some of the other effects of leaving the European Union.

The issue of whether British workers are being undercut by their foreign counterparts has been the subject of ferocious debate.

The Resolution Foundation – which is considered to be pro-immigration – analysed its effects, listing the areas which have seen the greatest change in their population profile.

It said that the proportion of migrants living in some English towns had increased by almost 400 per cent in barely a decade

In Mansfield, Nottinghamshire, the proportion of migrants has rocketed by 391 per cent, while in North West Leicestershire it is 357 per cent.

The report found that in sectors such as food and clothing manufacturing, more than 30 per cent of workers are migrants.

Those from nations that joined the EU in 2004 earn some £8.30 an hour, compared with around £11.10 for Britons.

Of the 20 areas with the biggest increase in immigration, the report said: ‘Some are particularly concerned about migration and voted to leave the European Union by large margins, including Boston which recorded the highest leave vote of 76 per cent.’ The report also reveals that 8.1million people living in the UK were not born in the country – up from 3.5million in 1993. They make up 16 per cent of the population.

Labour MP Frank Field said: ‘This is a welcome recognition that open borders have pushed down the pay of workers.

‘We need to move to a points system to control entry and over time ensure we are providing an adequate labour force with the skills needed.’

Labour MP Frank Field backed the claims made by the think tank

Stephen Clarke, policy analyst at the Resolution Foundation, said that if net migration were reduced to 99,000 as a result of Brexit, the wages of UK workers would be 0.6 per cent higher, or £152 a year. But he said the Bank of England had downgraded wage growth by 2 per cent in the wake of the referendum result, cancelling out any rise in British workers’ wages.

Mr Clarke added: ‘The impact that recent widespread migration has had on British-born workers is hotly disputed.

‘While there has been no effect on wages overall, increased migration has caused a slight drag on wages for some. However, those expecting a wage boost off the back of a post-Brexit fall in migration are likely to be disappointed.’

He also said firms that rely on cheap migrant labour will have to rethink their strategy or face ‘closure’, because British workers earn more than immigrants.

Research published in December by the Bank of England found the influx from Eastern Europe and elsewhere into catering, hotels and social care jobs had led to an average 2 per cent pay cut for some low-skilled staff.

The governor of the Bank of England also warned last year that the huge influx of foreign workers was threatening the economy by holding down wages.

Mark Carney said high rates of immigration helped explain why pay rises had been subdued for years. He said sluggish earnings threatened the UK’s recovery from the worst recession in a century.

A Government spokesman said: ‘We will make a success of Brexit and build an economy that works for everyone, not just the privileged few. Since the recession, the UK employment rate has grown more than any other G7 country.