Trump’s Split-Screen Persona on Blaring Display in Britain Visit

In the interview, he also cast his ban on transgender people serving in the military as an economic decision — an assertion at odds with what administration officials defending the ban have said. Mr. Trump also admitted having used the word “nasty” in connection with Meghan, Duchess of Sussex, Prince Harry’s wife.

Mr. Trump had set the stage for his second trip to Britain as president with other interviews, in The Sun and The Sunday Times, which are owned by Rupert Murdoch. Asked by The Sun’s reporter about criticisms that the Duchess of Sussex had made about him in 2016, when she was Meghan Markle, an American actress, Mr. Trump said, “I didn’t know she was nasty.” He later denied saying “nasty,” although it had been recorded.

On Wednesday, Mr. Trump acknowledged to Mr. Morgan he had said the word but sought to clarify the context: “I wasn’t referring to she’s nasty. I said she was nasty about me. And, essentially, I didn’t know she was nasty about me.”

Mr. Morgan was at his most adversarial when he asked why Mr. Trump claimed to support rights for lesbians, gay men, bisexuals and transgender people, but was enforcing a ban on transgender military recruits.

Mr. Trump, who in his 2016 campaign included transgender people among those whose rights he would support, repeatedly cast the ban as an economic decision. Mr. Trump suggested that transgender people were enlisting as a way to cover medical costs. He also suggested, falsely, that they cannot use prescription drugs in the military. Drug abuse is prohibited, but not prescriptions.

“They take massive amounts of drugs,” he said. “They have to.”

When Mr. Morgan interjected that the American military spends more money on Viagra for servicemen than on transgender medical bills, Mr. Trump was unfazed.

“Well, it is what it is,” he said. “Look, massive amounts — and also people going in and asking for the operation — you know the operation is $200,000, $250,000 — and getting the operation. The recovery period is long and they have to take large amounts of drugs after that for whatever reason, but large amounts, and that’s not the way it is. I mean, you can’t do that.”