Exclusive: The government has been urged to act on the findings of a Construction News investigation into working conditions on the Tottenham Hotspur stadium project.

Construction News has been told by workers on the scheme that many were working long hours as the handover deadline approached, and has also obtained evidence of workers being incentivised to undertake back-to-back 12-hour shifts.

The £800m project, which is being built by Mace, is nearing its completion date in time for the club to play its second home game of the 2018/19 Premier League season.

An email to staff from one subcontractor on the project, seen by CN, offers workers an extra four hours’ pay if they work four 12-hour shifts in a row.

CN has also discovered multiple job adverts, posted by recruitment agencies on a major UK job site, for roles involving 16-hour days and 80-hour weeks.

The posts call for workers who can take on “long hours” as the project “has to be kept to extremely tight deadlines”.

One night labourer advertisement requests workers who can do “80 hours per week”, while another for a handyman role advertises working hours of “8 hours a day to 16 hours”.

Responding to CN’s findings, a spokesperson for Mace said the contractor was “aware of the risks of overworking on such a busy project”, adding that the firm was carrying out random spot checks with subcontractors to make sure staff working longer hours were given breaks and rest periods.

There is no suggestion that Mace was involved in creating or posting the job adverts seen by CN.

A worker who left the project due to the working conditions, and spoke to CN on the condition of anonymity, described how the project’s intensity had increased ahead of a test event at the new ground in late August.

“All our supervisors came and said, ‘It’s crunch time, we need you to do a lot more work’,” they said.

The former worker said conditions on site had become challenging as more and more workers were brought in.

“There were so many people there when you were walking round the corner you’d nearly be being hit in the face by stuff. Compared to other jobs it just seemed very rushed.

“One of my colleagues – an experienced electrician – said he felt he should go to the Health and Safety Executive, he’d never worked on a site like that.

“He reckoned it was overcrowded and there were too many trades. There was an accident waiting to happen.”

The current total workforce on site is just over 3,800 people, CN understands, with around 100 staff being given a full health, safety and wellbeing induction on the project each day.

In May, Tottenham chairman Daniel Levy wrote an open letter to supporters which included an update on the stadium, saying “contractors with a workforce approaching 3,000 are working around the clock” as it battled to get the stadium completed for the start of the 2018/19 season.

In response to CN’s investigation, Labour’s shadow minister for labour Justin Madders called on the government to act to ensure those working on the project were doing so safely.

“Terms and conditions that put the welfare of workers at risk are unacceptable and the source of these adverts must be thoroughly investigated as a matter of urgency,” he said

“This is a high-profile project which should be founded on a gold standard of health and safety. A tight timeframe is no excuse for working conditions that can put people at risk.

“The government must act immediately to ensure all those working on Tottenham’s stadium are doing so safely and are not being forced to work dangerously long hours.”

A Mace spokesperson said the business would continue to work with Tottenham Hotspur to identify areas of improvement around health and safety as the project entered its final phase

They said: “As [is] normal with a project of this size, which is comparable to projects like the Olympic Park or Heathrow Terminal 5, during the final phases of construction activity ramps up.

“This will come as no surprise to anyone with experience in our industry.

“The health, safety and wellbeing of everyone working on our projects is our highest priority, and we are committed to making sure that everyone on our projects goes home safely at the end of each day.

“As with any project, there is always room for improvement, and we are constantly working with our client, supply chain and operatives to identify areas where we need to do better.”

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A Tottenham Hotspur Football Club spokesperson said: “Our stadium construction partners Mace are in control of the stadium site and we expect them to uphold the requisite welfare rights of all contractors.

“They have assured us that they supply the appropriate level of welfare facilities, in line with industry standards for a site of this size, and reiterated that the health and safety of all those on site is of paramount importance to them.”

A spokesperson for the Department for Business, Energy and Industrial Strategy said: “The UK has some of the most robust protections for employees and safest workplaces in the world.