Why Cameron went public over Blairmore shares
When a politician is under pressure, facing questions about their family and their finances, their natural instinct is to protect their privacy and say as little as possible.
But when that pressure gets too great, there comes a moment when they have to go public and for David Cameron that moment came last night.
In the long run, the prime minister will hope to achieve his aim of drawing a line under this story.
Journalists and opposition MPs will naturally keep asking questions.
But there are unlikely to be more significant revelations than the fact that Mr Cameron did indeed benefit from an offshore trust, something that is legal but over which people have differing views.
The problem for the prime minister is that the political imagery is not good.
He is engaged in the political fight of his life, trying to convince the British people to vote to stay in the European Union.
And anything like this, that distances Mr Cameron from the electorate, that reminds people of his wealthy and privileged background, well let's just say the timing is not great.