The two leaders sparred in the Commons on Wednesday afternoon just after reports that a number of Tory donors held accounts with HSBC in Switzerland, a section of the bank which has been accused of helping clients evade taxes.
The Labour leader told MPs that there was a "revolving door" between Conservative HQ and the bank, which is the largest financial institution in Britain, and said that Cameron had been caught 'bang to rights' by failing to vet the bank's chairman, Stephen Green, who he appointed as a coalition trade minister.
"He took the money. He gave a job to the head of HSBC. And he lets the tax avoiders get away with it. There is something rotten at the heart of the Tory party and it's him," the Labour leader rounded off, pointing at his rival across the chamber.
Cameron accused Miliband of "desperate stuff" in response, mocking the party over shadow education secretary Tristram Hunt's remarks about the quality of nuns' teaching. "They've even offended nuns, no wonder people look at Labour and say they haven't got a prayer," he quipped.
Stephen Green has been dragged into a furore over tax evasion as he used to chair HSBC before taking a Tory peerage and joining the coalition. The bank has been has faced accusations of helping clients cheat the UK public purse out of millions of pounds in tax by using Swiss bank accounts, according to an explosive treasure trove of leaked accounts.
See more on General Election 2015
Public accounts committee chairman Labour MP Margaret Hodge, chair of the influential Public Accounts Committee, said the former trade minister faced "serious questions'.
"Either he didn't know and he was asleep at the wheel, or he did know and he was therefore involved in dodgy tax practices," she went on. "Either way he was the man in charge and I think he has got really important questions to answer."
Lord Green was at the centre of another maelstrom in 2012 amid accusations that HSBC allowed drug king pins, terrorists and rogue nations to launder money through its global subsidiaries, with the Tory peer later expressing "regret" over the bank's role.
HSBC was forced to issue an apology after a United States Senate committee found that over the last ten years the bank had provided services to some lenders in Saudi Arabia and Bangladesh believed to have helped fund al Qaeda and other terrorist groups.
Now the details of 30,000 accounts holding almost £78 billion of assets are being revealed after they were obtained by a French newspaper and analysed by a team of investigative journalists, with the files reportedly including nearly 7,000 British clients.
In a statement to the Guardian, HSBC said: "In the past, the Swiss private banking industry operated very differently to the way it does today. Private banks, including HSBC’s Swiss private bank, assumed that responsibility for payment of taxes rested with individual clients, rather than the institutions that banked them. Swiss private banks were typically used by wealthy individuals to manage their wealth in a discreet manner.
"HSBC has cooperated and continues to cooperate to the extent that it can with requests for information from governments regarding account holders. However, providing client data to foreign authorities would itself constitute a criminal offence under Swiss law."