When Martin Brookes left the voluntary sector in 2011, after 10 years at New Philanthropy Capital, the think tank and impact measurement consultancy, he did not expect to be back so quickly.
Brookes joined the investment firm Fulcrum Asset Management as an economist, but only 18 months later he decided to return to the voluntary sector. In June, he became director of the Paul Hamlyn Foundation, a grant-giver with a £600m endowment.
"The charity sector is home," he says. "It took leaving to realise that. I've spent my time flitting from the public to private to voluntary sector. But this is where I belong."
Brookes has a reputation as one of the sector's strongest advocates for impact. Charities, he says, should constantly measure and demonstrate their effectiveness. Since he left NPC, he says, there has been some movement in the right direction.
"Someone said to me when I left NPC: 'You made it legitimate to ask the question about impact'," he says. "My heart sank a bit because I thought: 'Is that all I managed?' But at least we managed that. The question is on the table.
"The direction of travel is still the same. Some impact measurement is still poor and people are still doing it to satisfy funders - there is a bit of box-ticking - but slowly things are moving in the right direction."
But he still feels that the voluntary sector needs to get much better at explaining itself to the wider world.
"One of my first jobs in the sector was developing what became known as the full cost recovery model," he says. "That was partly about getting away from this idea that charities should be measured by their spending on administration costs. Now we're seeing a debate about chief executive pay, which is a similar red herring."
The public, he says, have a simplistic view of charities and should be judging them on their effectiveness, not on what they pay their staff. But he feels the sector must argue this much more clearly. "I was depressed by the fact that the sector didn't try to defend itself," he says of recent articles in the Daily Mail and The Daily Telegraph, which contended that chief executives in voluntary organisations were paid too much. "It is obviously an area of genuine concern for donors. There was an assault on the sector and it was met with silence. It wasn't met with a clear leadership voice - just fragments of responses. It raises the question: who are the advocates for the sector? Are they vocal enough?
"It should be someone's job to say: 'This is why things are the way they are.' Instead, our silence is an act of collusion with reductive and simplistic views of the sector."
Brookes is worried not only about the sector's effectiveness, but also about that of his own organisation, which is now embarking on a strategic review of its activities. Brookes says foundations must scrutinise themselves, because outside organisations have little power to influence them.
"The power imbalance between funders and those they fund is extraordinary," he says. "People are asking for money, so they have to deal with you on your terms. You are privileged that power lies with you and should do everything you can to even that relationship up."
He aims to have a "very public and open engagement process", he says. "Generally funders aren't as transparent as they might be, which magnifies the power imbalance. We're going to ask people to complete the statement 'Paul Hamlyn should... ' and leave it open. We don't want to control where it goes. We will use social media and try to get to the places other consultations do not reach."
Brookes, who admits he has "form" for being outspoken, says he is interested in whether foundations should speak out more on behalf of their beneficiaries.
"Foundations have independence," he says. "We don't want anyone else's money, so we can say what we like. No one will think we have an agenda or an angle because they know we don't want anything from them."
Although his foundation has made some social investments, such as the Peterborough prison social impact bond, he does not anticipate that it will invest large amounts of money in this field.
In general, Brookes says, a move from grants to repayable finance creates a moral problem, because it involves helping people because you have been paid to, rather than because you ought to.
"If you're helping child abuse victims because you're being paid to, it starts to make sense not to help some other people because it won't make you money," he says. "I wonder whether people realise what might happen if you move from a grant-based system to a market-based one."
2013: Director, Paul Hamlyn Foundation
2011: Economist, Fulcrum Asset Management
2008: Chief executive, New Philanthropy Capital
2001: Head of research, New Philanthropy Capital
1994: Senior economist, Goldman Sachs International
1987: Economist, Bank of England