Non-UK EU nationals make up more than a quarter of the construction workforce in London, according to official analysis.
It found 28% of those employed in the industry in the capital are from one of the 27 other EU member states.
Nationally, around one in 14 construction workers are non-UK EU citizens – referred to as EU27 nationals.
The figures were disclosed in a paper published by the Office for National Statistics (ONS) today.
Estimates from the annual population survey show that an average of 2.2m people worked in the construction industry between 2014 and 2016.
Seven percent of workers in construction in the UK are EU27 nationals, while 3% are non-EU, the report said.
It added: “In London, 28% of construction workers are EU27 nationals and 7% are non-EU nationals; this compares to 13% who are EU27 nationals and 10% non-EU nationals for all other industries in London (excluding construction).”
Of the 165,000 EU27 nationals in construction, it is estimated that just under half (49%) are from the EU8 countries that joined the bloc in 2004 – Poland, Lithuania, the Czech Republic, Hungary, Slovakia, Slovenia, Estonia and Latvia; 29% are Romanian or Bulgarian; 11% are from 14 longer-term member states; and 10% are Irish nationals.
Workers covered by the report include those working in commercial and home-building, infrastructure construction such as roads, railways and bridges, and specialised activities such as demolition.
The report said the construction workforce is ageing, with a 13% increase in the numbers of workers aged 45 and over between 1991 and 2011.
Non-UK nationals in the industry are younger (18% aged 45 and older) compared with UK nationals (47% aged 45 and above).
Two-fifths (41%) of construction workers were self-employed between 2014 and 2016, while a third of resident non-UK nationals in construction occupations are in “general labour”.
Labour MP Gareth Thomas, a champion of the anti-Brexit campaign group Best for Britain, said: “This data from the ONS should send a shiver down the spine of the government. We face the prospect of new homes, schools, hospitals and colleges not being built. “Housebuilding is heavily reliant on skilled EU labour. Although tens of thousands of UK-born workers have been recruited and trained in recent years, training more workers takes time and would not be enough to meet demand. Brexit could turn a housing crisis into a national disaster.’
The reliance of some sectors on migrant labour has come under close scrutiny after the Brexit vote.
Figures published last month showed the number of EU nationals working in the UK had registered an annual fall for the first time in eight years.
Officials are working to draw up post-Brexit arrangements which incorporate an end to free movement rules, while ensuring that any fall in overseas labour does not damage the economy.
The Home Office has commissioned the Migration Advisory Committee to report on the impact of exit from the EU on the UK labour market, with the full assessment due by September.