From today, employees effectively stop working to pay taxes and start earning cash to spend on themselves - according to research by a think-tank.
The so-called tax freedom day falls four days later than it did last year as Britons face greater state levies, the free market Adam Smith Institute said.
Its analysis found that tax receipts are projected to be 42% of net national income this year and take workers 154 days to cover.
The date has fallen in June for the first time in 15 years, which raises a "red flag" that the tax burden is moving in the wrong direction, the institute said.
Director Eamonn Butler said: "The Treasury hates tax freedom day because they don't want us to know how much tax we really pay. They conceal the tax burden with stealth taxes that we don't even realise we're paying.
"But it's shocking that the Government takes over two-fifths of the country's earnings - and then borrows more. We work longer for the Government than medieval serfs had to work for their lords.
"It is absurd that people on the minimum wage are liable for National Insurance contributions, which raise their cost to employers and make it harder to move from benefits into work. The poor are also worst hit by regressive taxes like excise duties on what they buy."
The institute found that while net national income had increased by £34.6 billion from 2015, the Government has taken up £35.4 billion more in taxes, leaving Britons £1 billion worse off than last year.
Conservative former Cabinet minister John Redwood said: "I think it is wrong that people have to work for the Government until June 3 and for their families and themselves for only a little over half the year.
"I want us to leave the EU so we have more of our own money to spend. The UK deserves a tax cut and leaving is the way to get it."