Our National Parks are getting less money from central government - some have seen their grant cut by 40% in the past 5 years. To make up the shortfall, they're exploring new commercial opportunities.

As well as coming up with individual fund-raising plans, the 15 National Parks in England, Wales and Scotland have formed a joint body, called National Parks Partnerships. It's exploring new ways of selling their collective logo: "Britain's Breathing Spaces". The idea is modeled on a similar organisation in the USA, which has done million dollar deals with companies like Disney and Coca-Cola.

So, how far should our parks go down the commercial route? Tom Heap investigates.

Producer: Chris Ledgard.