Gordon Brown has said former prime ministers “must never” lobby government for commercial purposes as he admonished David Cameron’s own efforts.
The former prime minister also chided ministers who allowed Cameron to lobby them through unofficial channels.
Brown told BBC Radio 4’s Today programme: “Former prime ministers must never be lobbying for commercial purposes. Current ministers should not be entertaining such lobbying.
“It simply brings public service into disrepute.”
If such situations could not be stopped, Brown said, news laws should be passed to stop former ministers lobbying for five years after leaving government.
The comments came after Cameron broke his silence on the controversy on Sunday saying he should have contacted ministers through “formal” channels but had not breached code of conducting rules on lobbying.
Under the current guidelines, senior civil servants and ministers are banned from lobbying for two years after they leave government, a rule Cameron followed.
The Sunday Times published a series of stories about Cameron’s lobbying efforts on behalf of Greensill Capital.
It revealed the former Tory prime minister texted chancellor Rishi Sunak and other Treasury ministers over access to government-backed emergency loans during the pandemic.
The paper also reported that health secretary Matt Hancock had met Cameron and his financier boss Lex Greensill for a “private drink” in 2019 to discuss a new payment scheme for the NHS.
An ally of Hancock said he had “acted in entirely the correct way”.
In a statement realised on Sunday, Cameron said: “I have reflected on this at length. There are important lessons to be learnt.
“In my representations to government, I was breaking no codes of conduct and no government rules.”
He added: “As a former prime minister, I accept that communications with government need to be done through only the most formal of channels, so there can be no room for misinterpretation.”
Labour is calling for an investigation into the matter.
Labour’s Rachel Reeves said: “The events unfolding over the last few weeks stretch across government and affect thousands of people.
“Transparency and accountability are crucial and that requires the utmost openness from government to establish the full facts behind this scandal.”