Conservative MP Oliver Letwin expressed his “regret” that charities focus so much effort on campaigning, just hours after NCVO chief Stuart Etherington and former Shelter head Adam Sampson lauded civil society's campaigning activities.

Letwin told delegates at the NCVO's Campaigns Conference that there were other groups who campaigned and that the “special contribution” of the sector was in being able to solve problems and change things.

“Charities are free to campaign, but what I treasure about the sector isn’t its campaigning role,” Letwin said. “We need a powerful sector which is able to deal with social problems, which the private sector and state can’t do. This is its real role. Campaigning is secondary.”

His comments came just hours after Etherington and Sampson, now chief ombudsman at the Office for Legal Complaints, had celebrated the sector's campaigns.

Stuart Etherington, NCVO’s chief executive, argued in his opening speech that campaigning was central to democracy.

He said: “Campaigning by charities…has often energised and provoked public debate in a way that has left traditional politics in its slipstream."

Sampson said charities needed to both “bite” and “stroke” government to campaign for change effectively.

“You can have a fantastic-looking brand by opposing everything that moves but that doesn’t necessarily make you an effective campaigner. Equally, if you never criticise, you will never get anywhere," he said.

“The threat you carry is that if they don’t let you in the room, you will bite their arse. It’s about when you bite and when you stroke.”