The National Trust are not radical but some of their work is good. You could make sure you are involved in environmental stuff rather than helping to preserve the homes of the rich.

mmmmmm natonal trust are ok but a bit conservative, i think they arnt family friendly and i think ther snotty.

I know someone prominant in the National Trust and unfortunately they have recently embarked on a centralisation system alienating national trust workers from democracy in the organisation. The centralised management team have imposed measures upon property managers to save costs such as reducing workers pay and staff numbers. This is despite the property in question increasing visitor numbers and therefore increasing profits. If you are joining the national trust be very wary they are target driven and therefore increasing property investments at the expense of workers rights. Join a union and be careful!