The RSPB nature reserve is the largest part of the park to be open to the public.

It was identified as a flagship project for the Thames Gateway in 2003 and a feasibility study was undertaken.

The project was a partnership between the London Thames Gateway Development Corporation, the Royal Society for the Protection of Birds (RSPB), the Mayor of London, the London Development Agency, Havering Council, Thurrock Council and the Thurrock Thames Gateway Development Corporation.

Plans for the park were set out in 2005, in a document endorsed by Bill Oddie.

When complete, it will form a 6.4 km2 (640 hectares / 1580 acres) conservation, recreation and amenity zone twice the size of Hampstead Heath.