Parts of the park date back over 1,000 years

The park around Calke Abbey covers more than 600 acres and contains a wood dating back at least 400 years.

The heart of the park is dominated by 200 oak trees, some of which are thought to date back to Saxon times.

The Derby South MP and Environment Secretary Margaret Beckett is visiting the Abbey to announce its new status.

Fiona Reynolds, the National Trust's Director-General, said: "Calke Park is a precious and fragile oasis which requires careful long-term management and conservation.

"We are very excited about the National Nature Reserve designation.

"It demonstrates the value of the work the National Trust is doing to safeguard and share the nation's natural heritage, not just for visitors today, but for future generations."