Work has started on a £5.5m project to transform a Grade II-listed castle at a Dorset nature reserve.

Durlston Castle, near Swanage, is being renovated and turned into a visitor centre for the Jurassic coast world heritage site.

It will form the centrepiece of the 280-acre Durlston Country Park and will house a shop and catering facilities.

A turf cutting ceremony took place earlier. The work is expected to be fully completed by July 2011.