Here's the full letter Mr Hain sent to Gordon Brown at lunchtime signalling his intention to resign:
Dear Gordon,
As we discussed this morning, in view of the Electoral Commission decision today, I have come to the conclusion that I now have no alternative but to resign from my posts as Secretary of State for Work and Pensions and Secretary of State for Wales, in order to give myself the time and opportunity to clear my name.
I have made it absolutely clear that I very much regret reporting donations to my deputy leader campaign late and I made this public as soon as I could.
When I discovered on 29th November last year that there was a problem, I saw the Electoral Commission as soon as I could and cooperated fully, including supplying all the details they asked for.
I made a mistake but it was an innocent mistake.
I am very grateful for the support you have shown me throughout this episode and for appointing me to your Cabinet where we have worked together to take forward the goals of social justice, equal opportunities and democratic reform in which I have always believed.
It has been a real privilege to head both the Department for Work and Pensions and the Wales Office, and a privilege to serve as a Minister in our Government since 1997. You will continue to have my absolute support.
I am fortunate to have the steadfast support of my wife Elizabeth, my parents and the whole of my family, and I am also very grateful for the support of my local Labour Party in Neath, of Labour MPs and Ministerial colleagues.
Best wishes, Peter.
Early favourite to succeed Mr Hain is Kim Howells, who would be entertaining in any number of ways. Howells may have spoken of having "shared values" with the leadership of Saudi Arabia and its lax approach to human rights, but whether he'd extend the same hand of friendship to Plaid Cymru's more trenchant AMs is another matter. Still, you can't argue with his views on modern art. Or rap.