A British banking bigwig who feared that he was about to be swept up in a finance probe and end up behind bars drowned himself in his swimming pool, according to a report.

Adrian Hill, 60, the former head of the HFC Bank, told his wife that he was going downstairs to make a cup of tea at their posh estate near Henley-on-Thames in South Oxforshire, the Telegraph reported.

But the despondent man, who had been suffering from nightmares, stepped out into the garden, crawled under the pool’s cover and slid into the water on March 29, according to an inquest.

The couple’s groundskeeper later found the body after a search.

In the early 2000s, Hill was one of the first pioneers of subprime mortgage lending in the UK, which was ultimately blamed for sparking the worldwide financial crisis in 2008.

He later went on to lead both First Direct and M&S Bank.

Recently, he clashed with the Financial Conduct Authority over its efforts to crack down on payday lenders, according to the news outlet.

In October, he called the watchdog “a very nasty bully” after blaming it for the bankruptcy of his rent-to-own business, leading to the loss of 700 jobs.

The FCA then threatened to call law enforcement authorities after Hill compared its staff to the Stasi secret police of the former East Germany. He also threatened to kill senior FCA officials and sent a picture of himself carrying a hunting rifle.

The watchdog also was investigating HFC amid allegations that thousands of credit card customers were overcharged when they fell behind with payments.

On Wednesday, a coroner heard that Hill had begun to suffer from manic episodes after becoming convinced that the FCA was closing in on him.

“He was talking under his breath and there was a lot of getting himself into a pickle and worrying about things, worrying about his paperwork,” Hill’s wife, Belinda, told the inquest.

“He was concerned that a regulator was going to come and arrest him.”

The coroner ruled Hill’s death a suicide.