John Oliver
John Oliver argued why Britain should stay in the European Union on "Last Week Tonight" on June 19, 2016. HBO

Is John Oliver in the "stay" or "go" camp? The British comedian is based in the U.S. and usually uses his HBO show to comment on hot-button issues stateside, but on Sunday Oliver weighed in on the biggest issue facing his home country: the upcoming "Brexit" vote.

Oliver waited until the last episode of "Last Week Tonight" before Britain's June 23 vote, on whether the U.K. should stay in the European Union or leave it, to give his view on the matter. While the host sympathized with some people's confusion and frustrations with the EU, Oliver argued that leaving the political-economic bloc of 28 nations would be a disastrous mistake.

"A Brexit could have wide-ranging implications not just for the U.K. but for the rest of the world's economy," Oliver said. "Immigration policy may not change, hysteria over regulation is a red herring, the cost of membership is reasonable, and the economic benefits of staying appear to outweigh the costs. And yet polls suggest that my homeland is on the edge of doing something absolutely insane."

Oliver went on to pick apart the various arguments for leaving the European Union, which in his view do not hold water. The comedian criticized a popular campaign that argues Britain would save £350 million a week by leaving the EU and could reallocate those funds for domestic benefit. Oliver explained that true figure is much lower and is a fair cost for the many economic benefits Britain gains from EU membership. He then showed a picture of the message splashed across the side of a bus in London before suggesting a new ad.

"We actually send the EU £190 million a week, which as a proportion of our GDP, makes sound fiscal sense. In fact, considering the benefits we reap in return…Oh s---, we’re running out of bus. Okay, bye-bye!” Oliver joked.

The comedian did express some sympathy for the large contingent of British citizens that polls suggest are currently in favor of the Brexit, noting that many Brits are subject to intense national pride.

"There is an innate British desire to tell Europe to go f*** itself," Oliver said. "I feel it too."

Oliver said his countrymen should nevertheless stay rational in the face of the big vote.