Harriet Harman has pledged to act as the "policewoman" in the cabinet who ensures that ministers show respect for MPs.

In her first interview as leader of the Commons, Harman told this week's House Magazine that the new emphasis on putting Parliament first must be enforced.

The deputy Labour leader has been put in charge of the government's relations with Parliament by Gordon Brown.

And Harman said the prime minister's promise that ministers make policy statements in the Commons before briefing the media was both welcome and necessary.

"That was one of the things that I said in my deputy leadership campaign, that I felt that people wanted to see no spin, no briefings, no leaking, respect for Parliament," she said.

"Everybody has recognised that there has been an erosion of confidence in our political institutions and a climate of cynicism," the minister added.

"This has not just been about the government. It has affected voter turnout and low voter turnout undermines the legitimacy of Parliament.

"This is a problem that needs to be addressed. This is a very important time to be taking over as leader of the House. Because what the House does and what happens in the House, everybody agrees, is critical to turning that [lack of legitimacy] around."

'Bad habits'

Harman accepted that "some bad habits became embedded" under Tony Blair.

"MPs were reduced to being an add-on to a debate that was already raging [in the media]," she said.

"MPs need to be able to set the debate by being the first to ask the questions. They are the most important because they are elected."

She also denied that Brown had set expectations at too high a level.

"People will judge us by how we do it," Harman promised. "Part of my job as leader of the House is to be the policewoman in the cabinet to actually make sure that colleagues do respect the House."

Modernisation

A long-standing champion of Commons modernisation, the new leader of the House insisted she is in "listening mode" on any future changes to MPs' sitting hours or working practices and that she will not be a "dictator" to MPs.

However she hinted that she would be a willing recipient of calls to introduce a new round of reforms.

"My record on sitting hours is one which has been consistent through the years," she said.

"People know where I stand on this. But there are many people who think, on the back of very big change, that we need to go further."

Harman also rejected Conservative criticisms that it is inappropriate to combine her Commons role with her party position as Labour chairman and deputy leader.

Record

She pointed to her record as solicitor general for four years, another job in which requires "the holder of that post to work in a bipartisan way in the public interest".

"I never muddled up the public interest... with the party political aspect of my work as an elected, Labour Member of Parliament," she said.

She called on MPs to "judge me on how I do the job".

"If people are concerned about the importance of the House of Commons and if they recognise that the role of the leader of the House of Commons is important, which it is, they should not criticise me until I have done something wrong," Harman warned.

"Don't undermine the office when I haven't even done anything yet."