British Prime Minister Boris Johnson (L) greets U.S. Vice President Mike Pence at 10 Downing Street in London, Britain, on Sept. 5, 2019. (Photo by Xinhua/Ray Tang)

British Prime Minister Boris Johnson has said that the NHS, the British national health service, is "not on the table" during any post-Brexit trade deal talks with the United States.

Johnson took the strong approach as he met visiting U.S. Vice President Mike Pence in Downing Street on Thursday.

"Of course, we will do everything to increase free trade but the National Health Service is not on the table as far as our negotiations go," he said.

Johnson drew the red line as his government is under attack that creeping privatization and a slackening of food safety standards would be the compromises for a trade deal with the United States.

British Prime Minister Boris Johnson (L) greets U.S. Vice President Mike Pence at 10 Downing Street in London, Britain, on Sept. 5, 2019. (Photo by Xinhua/Ray Tang)

Britain was "not too keen on that chlorinated chicken," Johnson added.

Pence, for his part, said the United States is "anxious"to strike a deal with Britain and a free trade agreement between the United States and Britain could increase bilateral trade by three or four times.

"We are anxious to do that and to stand with you and do everything in our power to strengthen what has been a historic and special relationship between the United States of America and the United Kingdom."

Nevertheless, Johnson warned that a deal with the United States must "work for all sides" as he pointed out that there remains quite some trade barriers in the U.S. markets.

"It is still the case, did you know, that the people of the United States of America do not eat any British lamb or beef or haggis from Scotland... I think there are still barriers to trade in shower trays, would you believe it, from the UK and many other products where we think we could free up the US market," said Johnson.

"I know that you guys are pretty tough negotiators, so we are going to work very hard to ensure that any free trade deal is one that works for all sides," he said.