Billionaire and Virgin Group founder Richard Branson published a blog post on Friday recalling his first interaction with Republican presidential nominee Donald Trump, in which Trump reportedly vowed to spend the rest of his life seeking revenge on five people who had refused to help him.

Branson said their encounter took place years ago, when Trump had invited him to a one-on-one lunch in his Manhattan apartment.

"Even before the starters arrived he began telling me about how he had asked a number of people for help after his latest bankruptcy and how five of them were unwilling to help," Branson wrote, although he didn't identify the five people.

"He told me he was going to spend the rest of his life destroying these five people."

Branson called the encounter "bizarre" and expressed concerns about Trump's "vindictive streak," which he said wouldn't bode well for a president who should be more concerned with global affairs than personal vendettas.

"I left the lunch feeling disturbed and saddened by what I'd heard. There are a lot of frightening things about this election," he wrote, "not least that policy has been pushed so far down the agenda."

Branson then compared the interaction with a lunch he had with Hillary Clinton, during which the two discussed issues such as women's rights and education reform. Clinton was a "good listener" and "eloquent speaker," and offered a stark contrast to her Republican opponent, Branson wrote.

"As she understands well, the president of the United States needs to understand and be engaged with wider world issues, rather than be consumed by petty personal quarrels," he said.

Branson, who is British, wrote a similarly critical post of Trump earlier in October, calling him "irrational," "aggressive," and "unfit for office," and praising Clinton.