Almost six million furloughed workers broke the rules by doing their jobs from home during lockdown, a study has claimed.

According to a new report, almost two-thirds of the 9.4 million people whose wages were being paid by the government still worked from home in April and May.

The study by academics at Oxford, Cambridge and Zurich universities claims there has been widespread abuse of the furlough system as businesses are strictly banned from claiming for workers if they are still doing their jobs in any capacity, the Mail on Sunday reports.

Rishi Sunak headed up the £30billion Job Retention Scheme which meant furloughed staff were paid 80% of their salary to a maximum monthly wage of £2,500.

Its purpose was to help businesses to survive after being forced to shut down for a number of months during the coronavirus lockdown.

Mr Sunak announced the scheme on March 20 – three days before the UK went into a lockdown – saying: “We want to look back on this time and remember how, in the face of a generation-defining moment, we undertook a collective national effort – and we stood together.”

The study, involving 9,000 workers, found not only was the ban on working “routinely ignored” but furlough staff worked on average 15 hours a week, men on higher salaries were more likely to work and a fifth of staff were ordered to continue working by their bosses.

It also found that seven out of 10 workers they studied were given a discretionary top-up from their bosses.

The study, the largest of its kind, claims 63 per cent of furloughed workers broke the rules and of those a third were told to do so by their bosses.

The report says: “The prohibition of working whilst furloughed was routinely ignored, especially by men who can do a large percentage of their work tasks from home.”

The biggest rule breakers were those with jobs in computing with the study claiming 44% continued to work while a third of workers in the information and communication sectors also breached the ban.

The blanket ban on working while being furloughed ended at the start of July.

The findings come amid claims that furloughed workers who have been forced to continue with their jobs have been contacting lawyers and whistleblower organisations for help.

Georgina Halford-Hall, the chief executive of WhistleblowersUK, told the Daily Mail: “The most shocking call we had was from a carer who was told they were furloughed, but told to keep working otherwise the people they care for wouldn’t be looked after.

“We also had a group of 15 people working on a building site who were told they had to keep working if they wanted a job at the end of the furlough scheme.”

One IT employee claimed they were threatened with the sack if they didn’t continued working and staff were “named and shamed” if their failed to hit their sales targets despite staff supposedly being furloughed.

HM Revenue & Customs is also looking into 8,000 tip-offs to its fraud hotline about illegal working.

It has also rejected 30,000 claims which it deemed dubious.

HMRC said it will pursue those who flouted the rules and they have sent out around 3,000 letters per week to companies suspected of breaking the law.

The government organisation is using “sophisticated computer software” to weed out culprits and bosses have 90 days to correct errors in their claims.

A HMRC spokesman told the Mail on Sunday they are “committed” to supporting the furlough scheme from abuse and they were investigating claims “in depth”.

But there are fears that some firms will get away with breaking the law.

MP Meg Hillier, chairman of the Public Accounts Committee which will question HMRC bosses on the issue next month, said the Government “needs to urgently get a grip on these issues around fraud”.

She added: “Employees are being put in incredibly vulnerable positions and employers need to face tough sanctions for this. We know people are trying it on and it’s right they should be tackled.”