WASHINGTON – British Prime Minister Boris Johnson had some dietary advice for Vice President Mike Pence when they met Thursday in London.

"We’re not too keen on that chlorinated chicken,” Johnson told Pence during a meeting that centered in part on the prospects of a United States-United Kingdom trade deal once Britain leaves the European Union.

Johnson told Pence that Americans don't eat enough British lamb and haggis. The prime minister pledged to work on an agreement "that works for all sides."

In discussions of a U.S.-U.K. trade deal, some British officials expressed concern that U.S. farmers engage in chlorine washing of chickens. The British prime minister used the issue as a political taunt against Labour Party leader Jeremy Corbyn this week.

In his meeting with Pence, Johnson said, "We have a gigantic chlorinated chicken of our own, here, on the opposition benches.”

What exactly is haggis? Let the BBC explain: "Historically, when hunters made their kill, they would use up the offal, which went off first, using the cleaned animal’s stomach as a cooking bag. Minced heart, liver and lungs are bulked out with oatmeal, onions, suet, seasoning and spices before cooking."

Pence in Ireland:Mike Pence has a deep affection for Ireland. It's not completely reciprocated

Pence said President Donald Trump authorized him to say, "We're ready to go to work on that free trade agreement just as soon as you're ready." Pence assured Johnson that Trump and the United States support "the U.K.'s decision to leave the EU – and we're ready to build this economic relationship immediately."

"Fantastic," Johnson said.

In a private meeting, Johnson and Pence discussed issues in Ireland, Hong Kong and Iran, according to a statement from the prime minister's office.

One topic that didn't surface in public remarks: Johnson's battle with Parliament, including members of his own party, over conditions for the British "Brexit" from the European Union and the timing of a possible national election.

Just before Pence's arrival at No. 10 Downing St., Johnson's brother – Parliament member Jo Johnson – announced he was leaving the body because he is "torn between family loyalty and the national interest."

Pelosi:House speaker calls Trump's properties 'cesspool of corruption' after Pence stayed at Trump hotel in Ireland