Best Start, formerly known as Sure Start (named Flying Start in Wales) is a UK Government area-based initiative, announced in 1998 by the then Chancellor of the Exchequer, Gordon Brown, applying primarily in England with slightly different versions in Wales, Scotland and Northern Ireland. It introduced a network of children's centres and other services to support local families with children under 5, including "health services, parenting support, early learning and childcare, and parental employment support". The initiative originated from HM Treasury, with the aim of "giving children the best possible start in life" through improvement of childcare, early education, health and family support, with an emphasis on outreach and community development.

Launched in 1998 by Tessa Jowell, Sure Start had similarities to the much older, and similarly named, Head Start programme in the United States and is also comparable to Australia Head Start and Ontario's Early Years Plan. The initiatives were subsequently bound together to form Sure Start Children's Centres, and responsibility for them was transferred to local government. Jowell subsequently commented in 2015, "I am very proud of setting up Sure Start, because the first three years of a child's life are absolutely critical in determining the chances they have subsequently."

The National Evaluation of Sure Start (NESS) project ran from 2001 until 2012. Initial research findings from NESS, published in 2005, suggested the impact of (the then termed) Sure Start Local Programmes (SSLPs) was not as great as had been hoped. However, by 2010, NESS could identify a significant impact on some of the outcomes set for Sure Start.

The Evaluation of Children's Centres in England (ECCE) project ran from 2009 until 2015. Results concerning the impact of (the subsequently termed) Sure Start Children's Centres (SSCCs) concluded that, "Children's Centres set up to support parents of young children can improve the mental health of mothers and functioning of families but that these benefits are being eroded by cuts."

In 2019, a study conducted by the Institute for Fiscal Studies concluded that Sure Start reduced the numbers of people taken to hospital, and saved millions of pounds for the National Health Service. Gordon Brown and other senior New Labour figures called for a "new Sure Start" in 2024 after a further IFS study on the programme's educational impacts found that "children who lived within a short distance (2.5 kilometres) of a Sure Start centre for their first five years performed 0.8 grades better in their GCSEs". Then-Shadow Chancellor Rachel Reeves refused to commit to expanding Sure Start in response to the report.

In 2024, the Conservative Government opened 400 new family hubs across 75 local authorities, which offer a wider range of services than previous Sure Start centres. In 2025, Sure Start was rebranded as Best Start and relaunched by the Labour Government of Keir Starmer, which announced an expansion of Best Start family hubs to cover every local authority in England, with £500 million allocated to create Best Start Services including Best Start Hubs. The plans aim for a total of 1,000 hubs to be open by 2028.

Initial funding was substantial, with £540M allocated for expenditure between 1999 and 2002, £452M of it within England, to set up 250 Sure Start Local Programmes (SSLPs) reaching up to 150,000 children in areas of deprivation.

The UK Government initially pledged to fund Sure Start for 10 years, but in 2003, Chancellor Gordon Brown announced the Government's long-term plan to transfer Sure Start into the control of local government by 2005, and create a Sure Start Children's Centre in every community.