John Hutton, the Work and Pension Secretary, will signal on Wednesday that he will press ahead with the reform, despite strong objections from Cabinet colleagues.

The Government will also announce new penalties for fathers who do not pay for their children’s upbringing, including curfews, the cancelling of passports and naming and shaming on the internet.

An aide to Mr Hutton denied that it was impossible to force mothers to declare paternity, and said that Whitehall discussions on how best to achieve this were well advanced.

The Opposition is to launch its own crackdown on errant fathers who abandon their families. Iain Duncan Smith, the former Conservative Party leader, will say today that the responsibility for poverty, school failure and crime should be laid at the feet of men rather than single mothers.

In his 300,000-word report, which will likely to please the right wing of the party, Mr Duncan Smith will call for tax breaks for married couples, arguing that the present tax credit system makes some couples better off apart.

Mr Duncan Smith’s research suggests that one in two cohabiting couples will have broken up before their child is 5, compared with one in twelve married couples.

David Cameron, the Conservative leader, welcomed Mr Duncan Smith’s conclusions, hinting that he is in favour of a tax cut for married couples. “If we are serious about tackling the causes of poverty and social breakdown, then we must look at ways of supporting families and also supporting marriage so that couples are encouraged to get together and stay together,” he said yesterday.

Family breakdown costs more than £20 billion a year, with 70 per cent of young offenders coming from lone- parent families, Mr Duncan Smith’s report says. It shows big variations between different sections of society. In 2001, 85 per cent of Indian couples with dependent children were married, whereas 50-60 per cent of black families were headed by a lone parent, typically the mother.

“We’ve looked at family breakdown, debt, drug and alcohol addiction [and] failed education,” he told the BBC.

“The results are bleak in the sense that we see now a growing underclass of people who give up hope of rising above it. We see no social mobility any more.”

However, an interview with The Sunday Telegraph threatens to overshadow the launch of the report. Mr Duncan Smith told the paper that gay couples were irrelevant to his work on shaping family policy for Mr Cameron. “We are looking at the issue of who brings up kids and the answer is it’s men and women that are the issue here,” he said.

Mr Duncan Smith insisted yesterday that he was talking about the statistical significance of gay couples and the impact that should have on Conservative policy.

The Government said that Mr Duncan Smith’s findings were crazy. “This looks to me like ‘back to basics’ all over again and I can’t believe that is where the Tories want to end up on this,” Mr Hutton told Sunday AM on BBC One.

The Government will announce this week details of the new body to replace the failed Child Support Agency. The new agency will focus on what Mr Hutton calls the “can’t pay, won’t pay brigade” instead of policing every payment.

“Although relationships end, responsibilities to your kids don’t. We’ve got to make life uncomfortable for the non- resident parents who aren’t paying for their kids,” he said.

A source close to Mr Hutton indicated that there might be exemptions to the new birth certificate rules for mothers who did not want their child permanently linked with the biological father — for example, if the father was a rapist.

Broken homes

Source: Social Justice Policy Group report

Times Recommends

• Hacker in final plea to stop extradition
• Lawyers? They're simply riveting . . .
• Companies slash legal spending