The two charities decided to join forces after surveys of their service users showed overwhelming support for a more holistic approach to service delivery across the UK.
Currently, Clic offers medical services to families of children with cancer, which complements Sargent's emotional support. They have had a loose partnership for some time, but from next year, this bond will become official.
David Ellis, Clic's chief executive, has been chosen to lead the new charity. He said: "We needed to bridge the gap on social care needs and medical needs because, at the moment, the two support teams often work side by side, but are managed differently."
Ellis added that while both charities are financially stable, the dramatic rise in income achieved by the merged Cancer Research UK had made both charities confident that they could increase their revenues as well.
Clic raised £7.9m from voluntary income in 2003, and Sargent Cancer Care £7.5m. "The opportunity to attract more support and donors is large," said Ellis. But he added: "There may be a slight fundraising hiatus when we start out because a lot of donors are emotionally attached to each side, but we must ensure that both sets of supporters follow through to protect our combined income."
Ellis called the merger a perfect fit and said the minimal duplication of job roles meant very few redundancies were likely among the 300-plus staff. All other senior management positions are expected to be decided by Christmas, and Siun Cranny, currently chief executive at Sargent, is said to be considering her options.