The partnership, which began in 2006, was originally intended to last three years but has been allowed to develop. About £560,000 has been raised since it began.
Ecclesiastical staff have donated more than 900 hours of staff time and been involved in fundraising events, gardening, reading to children and mentoring.
Now Ecclesiastical is supporting the work of the Children's Society through small grants to community projects, which arise from the charity's Good Childhood Conversations.
The conversations involve local people discussing issues facing children and young people. The grants support projects that emerge from those discussions.
Applications received so far have included a church-organised healthy living day and a school cafe for parents and children. £15,000 has been set aside for the grants.
"The partnership has changed in that we are looking at projects we can get involved in," says Liz Hunkin, sponsorship and partnership executive with Ecclesiastical. "The seed grants allow us to be very specific and to see tangible results."
It probably helps that both organisations have similar roots. Ecclesiastical, which is the Children's Society's insurer, is owned by a charity, the All Churches Trust, and the Children's Society - whose full name is the Church of England Children's Society - is allied to the Anglican Church.