The project's executive director, Christian Guy, said the princess was "excited" by the foundation's campaign and that the early years campaign was "rolling on as she recovers".

The foundation is calling on businesses to invest in supporting families with young children, such as more flexible working hours or help with childcare.

Produced by business leaders from companies such as NatWest, Aviva, the Co-op, Unilever and Deloitte, its latest report claims that the UK economy could make long-term gains of £45.5bn per year from a more successful approach to children's early years.

It claims that better early years education would eventually boost productivity in the workplace, more access to childcare would allow more parents back to work and more support would mean reducing the long-term costs of a neglected childhood, such as higher risks of ill-health and unemployment.

Emma Franklin, from Deloitte, which produced the report, said employers could help with cultural changes which would make it easier for workers with young children.

This could be something like not expecting staff to stay in touch on days off or not to expect replies early in the morning, before parents had dropped off children at childcare or nursery or school, said Ms Franklin.

She described it as "parenting out loud", where people were able to talk openly about the pressures of balancing parenthood with work.

Improving the experience of early childhood would have a "generational impact", she said, benefiting individuals and the economy.