Paul Flowers, former UK bank chief and political adviser, caught on film buying drugs (VIDEO)

LONDON, UK — A video and a string of leaked text messages have thrown Britain's banking and political worlds into turmoil.

In the two-minute iPhone video, a portly middle-aged man behind the wheel of a car chats with two companions about buying cocaine and crystal methamphetamine.

The man is Paul Flowers, 63, a Methodist minister, former adviser to Labour leader Ed Miliband and, until June, the head of Britain’s Co-operative Bank.

Detailing the extent of Flowers's drug use, the video and texts make clear that he was buying and taking drugs, while he testified before the House of Commons this month on the Co-op’s enormous losses during his three-year tenure.

The revelations have prompted a police investigation and a chairman’s resignation at the bank’s parent company.

On Wednesday, Prime Minister David Cameron accused Labour leaders of covering up for Flowers.

"Now we know all along they knew about his past. Why did they do nothing to bring to the attention of the authorities this man who has broken a bank?” Cameron said, from the floor of the House of Commons.

The news prompted serious questions about how a man whose only previous financial experience was a youthful stint as a bank teller was tapped to head one of the country’s biggest banks — and just how close he is to Miliband and the Labour Party.

Chancellor George Osborne is expected to order an official inquiry into how Flowers was deemed suitable to serve as the Co-op's chairman.

Flowers was suspended this week from the Labour Party and the Methodist Church.

Co-Operative Group chairman Len Wardle, who headed the board that appointed Flowers, also resigned Tuesday.

The video that started it all was posted online Sunday by the Mail on Sunday newspaper. Filmed from inside the car by a man named Stuart Davies, it shows Flowers driving to a drug deal in the north England city of Leeds.

“If I give you 300 . . . is that all right?” Flowers says while counting cash, which he hands to another man.

“What else have we got to get? Ket?” Flowers asks, referring to the drug ketamine. “No? Don’t worry, we can cope with what we’ve got.”

Here's the video, via The Mail:

Davies, 26, first met Flowers on the gay hook-up app Grindr in October. He gave the Mail the video and a string of text messages in which Flowers speaks openly of cocaine, crystal meth and ketamine use, and a party he describes as a “two day, drug fuelled gay orgy!!!”

On a day Flowers was scheduled to testify before the Commons about the Co-op bank’s $2.4 billion shortfall (he was bumped for lack of time), he texted that he was “snorting some good stuff.”

The bank is one of several businesses inside the Co-operative Group, a family of mutually-held retail businesses ranging from banking to grocery stores to funeral care.

The Co-operative Group has long had close ties to Labour. Most of its $1.4 million in political donations last year went to the Labour Party and affiliated politicians, including a $80,500 donation to shadow chancellor Ed Balls.

Flowers was one of 20 people appointed in 2010 to Miliband’s Business and Industry Advisory Group, an elite conclave that offered personal advice to the Labour leader on business policy before disbanding in 2012.

Flowers and Miliband met for private talks in the latter’s Commons office, the Daily Mail reported.

“He was involved in the Co-op and that is no longer the case. I think we will leave it there,” Miliband said when asked about the appointment Monday.

Flowers apologized for his “stupid and wrong” actions in a statement, blaming stress brought on by the bank’s troubles and the recent death of his mother. Police have searched his home.

In the wake of Flowers’s spectacular personal and professional destruction, many are asking how he was put in charge of one of Britain’s largest banks.

His background was in politics, the Methodist Church and the non-profit sector. He was chairman of the Lifeline Project, a drug and alcohol abuse charity.

He served as a Labour councilor in the northern England city of Bradford, but quit two years ago after “inappropriate but not illegal” adult material was found on his computer.

Flowers was tapped as Co-op Bank chairman in 2010, during perhaps the most turbulent point in the bank’s history. The year before, the Co-op completed what turned out to be a disastrous merger with Britannia Building Society.

Losses from Britannia’s loans helped bring the Co-op to the point of collapse.

In the first six months of this year, the Co-op recorded $1.1 billion in losses. A $2.4 billion gap in the bank’s finances emerged in May. Flowers agreed to step down.

Questioned Nov. 6 by the Commons Treasury Select Committee, Flowers delivered an underwhelming performance. He didn’t know the amount of loans on the Co-op’s books. He didn’t seem to understand what investments the bank had. He said the bank had $4.8 billion in assets — well short of its actual $75.6 billion.

Perhaps most startling was Flowers's revelation that his only prior experience working in a bank was a four-year stint as a teller in his 20s.

“I took the exam of the Institute of Bankers,” he said when asked about his qualifications. “I would judge that experience is out of date in terms of needs of contemporary banking.”

The next day, he texted Davies: “I was grilled by the Treasury Select Committee yesterday and afterwards came to Manchester to get wasted with friends.”

The scandal has been a black eye for Britain’s financial regulators. In the wake of the 2008 financial crash, the Financial Services Authority, the body that oversaw Britain’s banking industry, pledged better scrutiny of bank chiefs.

Two years later, it approved Flowers’s hire.

The FSA was aware of Flowers’ limited financial experience, wrote BBC business editor Robert Peston, but believed that his political skills would help tame the bank’s unruly board. (The agency has since been broken up into two new regulators.)

“To state the bloomin' obvious, regulators at the defunct FSA and its successor body, the [Prudential Regulation Authority], have a few questions to answer, about why they gave the thumbs up to Mr Flowers,” Peston wrote.

Flowers can be “very gifted as a speaker either in the pulpit or the council chamber, and at the same time he can be subject to incredible lack of judgment,” his friend and fellow Bradford councilor Geoff Reid told BBC Radio.

“I don’t think the Co-operative Bank got the political nous they thought they were paying for."