The Tory leader dismisses talk of renewed infighting

Amid reports of a fresh bout of Tory infighting breaking out over the departure of key officials, Mr Duncan Smith said the public had never even heard of most of the people involved.

But what is clear is that not everyone in the Conservative Party is singing from the same hymn sheet.

So what's it all about? Here's BBC News Online's guide to the key players in the latest Tory saga.

Modernisers vs traditionalists

Mr Duncan Smith baulks at the labels given to parts of his party, but it is how the current splits are being portrayed - by many MPs as well as the media.

The modernisers are most associated with former leadership challenger Michael Portillo.

They believe the party must appear more socially liberal, welcoming people who do not want to get married or are gay, for example, and taking a softer line towards drugs like cannabis.

Portillo was most modernisers' choice for leader

Such changes, as well as making the party look more representative by recruiting more female and ethnic minority candidates, are necessary to reach out beyond the core Tory vote, they say.

Public services must be at the heart of the Tory agenda, and the idea of lower taxes must not be allowed to confuse that message, they argue.

The traditionalists, by contrast, are wary of too much attention being spent on what they see as "fluffy" issues like the party's image.

Instead, they argue that a more Thatcherite Tory agenda of tax cuts, promising more freedom to individuals and offering tough policies on asylum and law and order are key to a Tory revival.

They believe talk of quotas of women candidates is a distraction - or even an irrelevance - when the party should be capitalising on Labour failures and putting "clear blue water" between itself and the government.

Traditionalists generally voted for Mr Duncan Smith and David Davis in the leadership polls.

Departing officials

The latest row started when Tory chief executive Mark MacGregor was moved away from Conservative headquarters to work on Steve Norris' campaign to become London mayor.

A former supporter of Michael Portillo's failed leadership challenge, Mr MacGregor was seen as an arch moderniser.

Barry Legg is the new chief executive and chief of staff

He wrote much of Tory chairman Theresa May's speech at last year's Conservative conference, where she said the party had to ditch their "nasty" image.

As the driving force behind that conference, he has also been credited with the party's stress on "helping the vulnerable".

With him last week went Rick Nye, the Conservative director of research, another ally of the modernisers who left by "mutual consent".

After working for David Owen and the SDP in the early 1990s, Mr Nye entered the Tory fold under John Major's leadership and stayed at central office during William Hague's tenure.

Those most recent exits follow the departures last year of strategy director Dominic Cummings and chief of staff Jenny Ungless, two more officials seen as signed up to the modernising agenda.

Change at the top

Traditionalists are delighted by the choice of new joint chief executive and chief and staff, Barry Legg.

Right-wing Eurosceptic Mr Legg was MP for Milton Keynes South West from 1992 to 1997.

He was one of Mr Duncan Smith's fellow Maastricht rebels in the early 1990s, published right wing pamphlets about tax and social security and backed John Redwood's 1995 leadership challenge against John Major.

The new top official has denied reports he nearly joined the UK Independence Party before the last election.

Who's unhappy?

Mrs May on Wednesday held meetings with some members of the Conservative board, who are believed to be angry they were not consulted about the shake-up.

David Davis is seen as a key traditionalist

Initially, few modernising MPs went public with their concerns, but privately they talked about the party committing "kamikaze on a slow guard mower".

Now former shadow chancellor Michael Portillo has broken cover, saying Tory chairman Theresa May's position now looks impossible.

Mr Portillo also accused Iain Duncan Smith of surrounding himself with yes men and of manufacturing a crisis out of thin air.

The smiling faces

Traditionalists like John Redwood, tipped for a return to the front bench, have a new spring in their step.

Mr Redwood said a new team at party HQ would help the party widen and deepen its programme, stepping up from attacks on Labour to offering Conservative alternatives.

Other traditionalists privately say the changes mean the modernising agenda is dead and the Tory leader is now surrounding himself with people he can trust.

Mr Duncan Smith says the changes do not interest the public, and instead points to recent opinion polls suggesting he is closing the gap on Labour.