The invisible men

The problem is especially acute in London. Building has evidence that huge numbers of illegal immigrants who speak no English are working on almost every site in the capital, including government projects and schemes operated by the Major Contractors Group.

"Ministers are turning a blind eye towards the problem," says Martin Slade, general secretary of the Immigration Service Union. "They know that if they cracked down on illegal workers, the cost of public projects would go up. It would be inflationary. This situation suits the government."

Bob Blackman, national secretary for construction at the T&G union, agrees: "The government has had an open-door policy for construction workers. The abuses on government projects are just as bad as on private projects. To say they don't know about it is unbelievable."

Blackman suggests that the government is avoiding the issue because tackling it would be too expensive and too disruptive to the construction economy. "You'd end up removing a large percentage of the workforce," he says.

Government departments appear to be deliberately neglecting their duties in order to disguise the scale of the problem. There are an estimated 1 million illegal immigrants in the country, but no official estimates exist for the numbers working in the construction industry.

The Home Office's immigration service – whose efforts to apprehend illegal immigrants entering through the Channel ports are widely publicised – appears to make almost no effort to pursue the thousands who have slipped through the net and are working on construction sites.

There is only one recent instance of the immigration service taking action. In April, 140 illegal construction workers – mostly Polish - were picked up in Southampton and deported. Detective inspector Tony Harris, who led the investigation, admitted that the case was the "tip of the iceberg", but said the police could only act when asked to do so by the immigration service.

A Home Office spokesperson denied the department was failing to act, saying: "There is a lot of work going on to identify illegal workers. There are operations daily." But he admitted the construction industry was not a priority and said the department does not actually hold figures for illegal workers apprehended in construction.

The Inland Revenue similarly appears to ignore the widespread tax and national insurance fraud that goes hand-in-hand with the employment of illegal workers, and which makes up a significant proportion of the industry's estimated £10bn black economy. The ISU's Slade estimates that there are 20 million bogus NI numbers in circulation, many of them used in construction.

An Inland Revenue spokesperson denied negligence, saying: "The building industry comes under the eye of the IR. The whole country, top to bottom, east to west, is covered by our web."

Strange then, that no construction firm has been prosecuted for tax or national insurance fraud in the past five years. "It's a question for the Home Office as to why they're not taking any action," says Bill Tallis, director of the MCG. "I haven't heard of any raids."

"Why doesn't the government organise raids on these sites?" asks the ISU's Slade. "Our suspicion is that it suits them too much." Slade points out that an invisible, illegal workforce makes no demands on the benefits system, costs nothing to regulate and neatly solves labour shortage problems. "Illegal immigrants can't make claims – so they're cheap to have on board."

Ministers know that if they crack down, the cost of public projects would go up

Martin Slade, general secretary of the Immigration Service Union

An English electrician working on a London site agreed that the authorities are not interested. "About 10 years ago, the social security department raided some sites," he said. "But since then, there haven't been any raids. The government doesn't want to know."

The government has even failed to enforce mandatory security checks on workers on its own sites. The problem came to light last month when, following the terrorist attacks in New York, departments ordered a clampdown to prevent terrorists infiltrating sites. Contractors working on projects for government departments and agencies suddenly had to implement measures such as checks on agency workers' backgrounds and political affiliations.

As a result, dozens of workers, many of them from Eastern Europe, were kicked off sites. On one project alone – the refurbishment of a departmental office in Whitehall – 23 workers are understood to have been removed. "To suddenly start enforcing procedures you hadn't bothered with for the previous 24 months really says everything," comments Blackman.

The government's negligence suits the construction industry, too, with leading firms readily exploiting illegal labour. A confidential survey of 20 sites operated by MCG members in the City of London found "dozens" of illegal workers – particularly Eastern Europeans - on every site visited. The survey, compiled by one of the leading unions and seen by Building, includes sites run by the biggest, most prestigious firms in the industry. The officer who visited each to conduct the survey, said: "Eastern Europeans are now on every site in the City in huge numbers."

The survey is backed by research carried out by Building reporters, who spoke to legitimate workers outside six of the City sites identified in the survey. The workers confirmed the survey's findings.

And yet, the illegal workers were nowhere to be seen, remaining on site during their breaks. Site hoardings, strict security and the fact that immigrants are bussed in and out means the problem is effectively hidden from view.

Informally, contractors acknowledge the existence of the workers. "It's a fact of life," says a spokesperson for one. But when challenged, firms pass the buck by blaming labour agencies and subcontractors for failing to screen workers. "Our members don't set out to employ illegal immigrants," says the MCG's Tallis. "They must be being passed on by agencies or subcontractors." But he described Building's evidence as "very interesting information" and admitted it pointed to "a significant health and safety issue".

An electrician working on a site run by a well-known contractor at London Wall agreed that the agencies were to blame. "They'll take on anybody," he said. "As long as at least one of a group of blokes can speak a bit of English, the rest can come on board."

One project manager at a City site told Building that contractors were aware of the situation. He said illegal workers approached him at the site entrance almost daily and he always turned them away. However, he never questioned the legitimacy of workers supplied by agencies. "They could be the same people," he admitted.

Agencies and subcontractors regularly provide even the most prestigious sites with immigrant labourers without documentation, NI numbers, health and safety awareness or knowledge of English. Workers are recruited on street corners after a cursory conversation about the daily rate. It is claimed that some agencies are little more than gangs who round up and deliver workers in exchange for a cut of their wages.

Two-and-a-half years after a Building investigation exposed how agencies illegally pick up labourers from a street in Cricklewood, north London, the practice goes on – despite promises by the authorities to investigate. Building visited the street on two occasions this month and saw dozens of vehicles – some bearing the names of well-known firms – approach Eastern European labourers to offer work on sites (see Dawn trade, in factfile below).

Although workers of almost every nationality can be found on British sites, the recent influx of Eastern Europeans is causing most concern. The largest group are economic migrants from Albania, many of whom have entered the country illegally through the south-coast ports or the Channel Tunnel. Many immigrants claim to be asylum seekers from Kosovo but the ISU believes a lot of these, too, are Albanians. There are also significant numbers of Poles, Ukrainians and Russians. All have been drawn to Britain by the promise of work with no questions asked, taking advantage of the labour shortage and replacing Irish labourers who left when their home country underwent a construction boom.

Eastern Europeans are now working on every site in the City in huge numbers

Union officer

Industry figures such as the T&G's Blackman are aware that raising concerns over foreign workers could be construed as racism and are careful to point out their prime concern is for the welfare of all workers – both British and foreign. "If people are legitimately employed, we want to look after them. But there's a statutory duty not to employ people who are not meant to be there."

Lack of language skills is the union's biggest concern, Blackman says. "The reality is that method statements, safety policies, briefings, videos, codes and so on are all in English. If you don't read English, you're going to be at risk." Stories abound of injuries caused by workers misunderstanding shouted warnings, failing to follow written instructions, or being ignorant of guidelines given out in English. According to another senior union figure, accidents caused by – or to – workers who cannot speak English are hushed up, making health and safety figures "meaningless".

"How can you work safely if you can't speak the lingo?" says the London Wall electrician, recounting a tale about a shop steward who was dismissed from a prominent development in Docklands for refusing to work with labourers who could not speak English. "He was ticked off for being racist – but actually he was worried about them not being able to speak English."

British workers are generally tolerant of their foreign counterparts, though they admit they are worried about the future. "It's all well and good at the minute while there's work around but what about when the recession hits?" asks the electrician, fearing he will be undercut by cheap immigrant labour. "I get £90 to £100 a day. They get £60. We work until 4pm, they work until 6pm."

But others argue that an illegal workforce will soon move on if there is a downturn in the economy, whereas registered and qualified workers are more likely to stick around to compete for dwindling work.

The government and the industry are finally beginning to face up to the issue. Last month, home secretary David Blunkett unveiled plans for "green cards" allowing foreign workers to apply for a restricted number of permits to work in this country during periods of labour shortage. At the moment, non-EU workers must have job offers from UK firms before they can enter the country. But Blunkett proposes to issue only 40,000 cards each year – 10,000 for the construction industry. This is unlikely to do much to stem the 150,000-200,000 people the ISU estimates enter the country illegally each year.

The green card proposal is rejected by Tony Merricks, chairman of the Construction Skills Certification Scheme, who is instead calling for a Europe-wide skills certification scheme. "The government's proposals for a green card system won't do anything for ensuring site safety or improving the industry's skills base," he says. Instead, the Europe-wide scheme "would set standards across Europe and would allow for the fact that construction workers traditionally comprise a migrant workforce", he says.

But the CSCS proposal is not designed to solve the Eastern European problem; these workers come from outside the European Union and would not therefore be eligible for the scheme.

The T&G's Blackman proposes more modest changes, calling for all health and safety material to be produced in workers' own languages. Although this might improve safety, the plan would do nothing to eradicate the black economy or end exploitation of workers.

The MCG claims its new health and safety charter will eradicate illegal workers on members' sites. The charter calls for a fully qualified, legitimate workforce by 2003. "IDs and cards will increasingly be checked," said Tallis. "They're going to find it increasingly difficult to get on site." But Building's investigation questions the credibility of the MCG's charter, which its members are already supposed to be phasing in. Nor will it stop immigrants working on non-MCG sites.

The situation on construction sites is not unique: hundreds of thousands of illegal immigrants are also being exploited in industries such as agriculture and tourism. The welfare of a million people is the concern of everyone, says Blackman, but ultimately it is the government's duty to address the problem.