THE Prime Minister this week pledged to put families at the heart of government policy, promising to carry out a "family test" on every new policy his Government introduces.

From October, every new domestic policy "will be examined for its impact on the family", Mr Cameron said. The Work and Pensions Secretary, Iain Duncan Smith, is to take on responsibility for all relationship policy.

After the announcement on Tuesday, Mr Cameron addressed the Relationships Alliance Summit, in which he spoke of how "incredibly lucky" he was to have his wife Samantha and four children. His oldest son, Ivan, who was severely disabled, died five years ago, aged six.

He said: "It's family that brings up children, teaches values, passes on knowledge, instils in us all the responsibility to be good citizens, and to live in harmony with others. Long before you go to the welfare state, it is family that is there to care for you when . . . you fall on tough times."

He also praised the "truly inspirational single parents in our country who do an amazing job bringing up their children"; and he said he was committed to same-sex couples' being able to adopt.

He also promised that funding for relationship-support services would stay at £7.5 million a year; and he announced an extension to the troubled-families programme, so as to reach another 400,000 families. Children will also be protected from graphic content in online music videos, with a scheme to pilot age-rating of videos.

In his closing remarks after the Prime Minister's speech, the chief executive of Marriage Care, Mark Molden, said: "Relationships are the hidden assets behind a . . . cohesive society, and it's time to unlock their potential."

Charities have welcomed Mr Cameron's commitment to families. The chief executive of CARE, Nola Leach, said: "We are very much encouraged to hear the Prime Minister acknowledge that tackling family and relationship breakdown remains a priority for the Government. CARE has long encouraged the Government to adopt policies that support and encourage fruitful family life, and today's comments from the Prime Minister are very welcome.

"Although we have been disappointed by some of this Government's actions and policies, there have been a number of positive steps, such as the Prime Minister's leadership in promoting improved protection of children online."

The charity Barnardo's welcomed the Prime Minister's focus on the impact of government domestic policies on families, and the expansion of its troubled-families programme, but called for more early intervention. In a statement, it said: "Barnardo's wants to see a major shift in public policy towards early intervention. Children in troubled families need much greater support, and they need it far earlier. The scale of the need is enormous. With 500,000 troubled families, there are likely to be up to a million children suffering problems at home."

Others wanted more detail about the proposed "family test".The advice and rights manager at Child Poverty Action Group, Paul Treloar, said: "We hope the proposed test does assess the impact of policies on all family types."