08/04/2016 13:35 BST | Updated 09/04/2017 06:12 BST

David Cameron's Spectacular PR Fail Over His Offshore Tax Haven

In his days as corporate affairs director at Carlton Television, David Cameron would doubtless have advised that the cover-up is always more damaging than the original sin of omission.

It's one of the first lessons of crisis management and it's a scenario we've seen played out over and over again at Westminster, which makes it all the more surprising that the Prime Minister handled the furore over his father's offshore fund so badly.

News of the mass leak of 11million documents from the Panama law firm, Mossack Fonseca, first broke on Sunday evening. Initially, the world leaders caught up in the data leak were Iceland's prime minister Sigmunder David Gunnlaugson and Russia's President Putin - not a man who has to worry too much about reputational impact.

But by 11am on Monday Downing Street was issuing its first statement about Blairmore Holdings, the Bahamas-based company set up by Mr Cameron's late father. Asked if the Cameron family still had money in the offshore fund identified in the Panama Papers, a Downing Street spokesman said: 'That is a private matter. I will focus on what the government is doing.'

As a response, that was never going to suffice. The 'I'm too busy to deal with trivialities, I'm focusing on my real job' is a stock PR weapon, but it always comes across as evasive. Did the Prime Minister's spin doctors really think they could hold the line when offshore tax havens have been such a hot political issue for the duration of Mr Cameron's premiership?

By Tuesday, the position had shifted. It was no longer a private matter. Asked if he or his family had benefited from any offshore fund in the past, or would do so in the future, Mr Cameron replied: 'In terms of my own financial affairs, I own no shares. I have a salary as prime minister and I have some savings, which I get some interest from, and I have a house, which we let out while we are living in Downing Street, and that's all I have. I have no shares, no offshore trusts, no offshore funds, nothing like that. And, so that, I think, is a very clear description.'

It was not a clear description because Mr Cameron chose to answer the question he wanted to be asked - about his current status - rather than the one he had actually been asked about the past. That was an error of judgement. It made for a good instant sound bite and gave the appearance of transparency, but in fact was simply a hostage to fortune.

A couple of hours later No 10 thought it necessary to clarify matters with another statement: 'To be clear, the Prime Minister, his wife and their children do not benefit from any offshore funds. The Prime Minister owns no shares. As has been previously reported, Mrs Cameron owns a small number of shares connected to her father's land, which she declares on her tax return.'

Except that the statement did not clarify anything because it still failed to address the question Mr Cameron had been asked about past ownership.

The fourth statement on the issue, released the following morning, also failed to address it. A Downing Street spokesman said: 'There are no offshore funds/trusts which the Prime Minister, Mrs Cameron or their children will benefit from in future.'

The No 10 spin doctors seemed to believe they could contain the issue by continuing to dance on the head of a pin. It's never an approach that a public relations expert would recommend because, under scrutiny, it invariably unravels. That's true even of a mid-size business, let alone a political leader who is questioned weekly in Parliament and regularly interviewed by journalists.

So, on Thursday, when interviewed by ITV's political editor Robert Peston, the Prime Minister was forced to admit he and his wife had held a stake in his father's fund for 13 years that was sold for £31,500 shortly before he entered Downing Street.

Given he had previously described investing in offshore schemes as "morally wrong" this was quite an admission, but how much better to have disclosed it at the start of the week and got it out of the way rather than having it dragged out of him after days of drip-drip political damage. The headlines were universally terrible, the story splashed across every front page.

Mr Cameron said he had "nothing to hide". To which, the obvious response is: 'Why not tell us in the first place?'