Mr Duncan Smith was party leader between 2001 and 2003

Mr Duncan Smith appeared close to tears as his speech on social justice got the longest ovation yet at this year's party conference in Blackpool.

He aimed his message at Gordon Brown saying: "British society is broken and it's time you admitted it."

He led the party from 2001-2003 but quit after losing a vote of confidence.

Mr Duncan Smith has been heading up the party's social justice policy group, which aims to tackle "social breakdown".

As much as Mrs Thatcher changed the economy, our duty is now to change society for the better Iain Duncan Smith

He said rising violent crime, family breakdown, and drug and gang culture showed society was "broken" and he called for tax breaks to bolster marriage.

Other proposals include a reform of welfare benefits and an expansion of credit unions.

"As much as Mrs Thatcher changed the economy, our duty is now to change society for the better," he said.

He told party members: "All I ask of you, when you leave this conference, is to be so committed that this becomes your life.

"Remember one thing, together we can change it, so come with us and let us mend our broken society."

He also won much applause for his criticism of Labour activists' ambitions to "destroy" the Conservative Party with a fourth election victory.

He said: "We must want power to rebuild Britain and to care for the British people."