It is Sir Stephen Bubb's first day back at Acevo, and he waltzes between the desks offering jovial greetings to his staff. He has spent the past eight weeks in a sixth-floor attic at the Department of Health, surrounded by civil servants and fellow members of the NHS Future Forum, the group hastily convened to advise the government during its 'listening exercise' on NHS reforms.
"It was bloody hard work," he says of his time chairing one of the forum's four panels, which produced a report about choice and competition in the NHS. "This was the most controversial element of the bill, and they asked me to take charge of a review of it. I said to David Cameron that he had given me the political hot potato." How did the PM respond? Bubb laughs: "He just smiled at me."
It was frantic, he says: "We were brought in during a crisis, and the process was rough and ready. As far as I can tell the whole thing was set up in about 48 hours. I had sleepless nights in a way I never had before, and I was working crazy hours."
But he never considered saying no. "It would have been absurd to turn it down," he says. "This was a huge opportunity for a third sector leader."
Was it potentially compromising, though, particularly if the listening exercise makes little impact on the bill or fails to give the voluntary sector an important role? He shakes his head. "If you take that view, you might as well say we'll have no involvement with the government whatsoever," he says. "Frankly, it's a juvenile attitude. To say 'they might do something naughty, so don't talk to them' is not how Acevo operates."
But has his organisation become too close to the government? Bubb dismisses the charge as ridiculous. "No organisation in our sector has been more critical of the government on cuts," he says. "In the middle of this process our Commission on Big Society reported - it's not a lickspittle publication. I don't think anybody would dream of saying I was too close to the government."
He says he made his independence clear from the beginning. "Although technically they paid my salary while I was there, I was absolutely not a civil servant and I was free to say what I liked," he says.
He did, however, take the advice of civil servants to turn down a BBC interview. "They occasionally made suggestions about press handling," he admits. "But it was always clear that I would make the decision, and I did. During the exercise I spoke to the Financial Times and the Today programme. I didn't even clear the Today interview with the department; I just told them I was doing it."
A main recommendation of Bubb's panel was a 'right to challenge' under which charities and community groups could mount legal challenges to the commissioning choices made by the proposed new GP consortia. Bubb has acknowledged, however, that this might not be adopted. "The official response was not as enthusiastic as I would have liked, but the government didn't reject it," he says. "It needs more work, but I'm still hopeful it will happen. I'm hoping it will be brought in as an amendment when the bill is in the Lords."
The report has also caused controversy because of its stress on competition and the need for private sector involvement in the NHS. "Since the listening exercise ended, the Liberal Democrats have been busily saying that, as a result, competition is in its box," Bubb says. "Well, competition is not in its box. Our report has said it is important."
Is he concerned that this stance will put him at odds with many in the voluntary sector, who fear that competition unaccompanied by fair commissioning leads to their defeat by large private companies?
"We do have to get over the idea that the private sector is full of wicked, evil people," he says. "It includes companies like Boots, which has played an important role in offering some medical services. The view that we shouldn't have private sector involvement is ideologically crackers.
"Of course, you need good commissioning, and our report says that. I don't know whether the health service at a granular level will be able to implement that more enlightened commissioning process, but you can't base health policy on charities' nervousness that it will not."
Bubb's tone seems to have softened since he warned The Times last week that the government must not "cherry-pick" which of the Future Forum's recommendations to implement.
"Our work has meant that people are talking about things like the right to challenge, personal budgets and the choice mandate, and they were not doing this eight weeks ago," he says. "Even if some of this is implemented in a more limp fashion than I would like, we're still in a better place than we were when this process started."