Leadership battle: what happens next?

Defeat for Iain Duncan Smith in the vote of confidence would trigger a lengthy and bruising leadership contest.

Mr Duncan Smith needs a simple majority of the votes cast in a ballot of the 165 Tory MPs to survive as party leader.

Victory would rule out any new challenge for 12 months under the complex rules introduced by predecessor William Hague to shore up his leadership.

But if he fails, Mr Duncan Smith will be barred from standing in the ensuing battle for the Conservative crown.

The field is then open to leadership hopefuls whose names have been the subject of mounting speculation at Westminster for weeks.

They face a series of knock-out ballots that will whittle that field down to two.

The survivors then go head to head in a nationwide ballot of rank and file party members.

It took three months to elect Mr Duncan Smith from a field of five candidates and a similar number are expected to stand this time.

Another damaging battle could only be avoided if MPs united behind a single candidate standing on a "dream ticket" with a deputy from another faction of the party.

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