If you work and pay into a pension scheme it is possible to put pressure on corporations you disagree with. Since last July ALL pension funds are required by law what (if any) ethical investment strategy they have.

Pension funds are by far the biggest shareholders in the UK, this means if you pay into a pension scheme at work you will be invested in all kinds of dodgy companies you disagree with. Ask the person who deals with your work pension scheme whether they have an ethical investment policy, if not put pressure on them to do so - they are legally required to act in the interests of beneficiaries - ie you.

point them in the direction of  http://www.justpensions.org/

you can argue that by investing in companies that are socially irresponsible (Exxon springs to mind) they are not looking after your interests. the argument is that as Exxon is climate change sceptic and the EU has now signed up to a (weakened) Kyoto protocol Exxon will be at a disadvantage economically (because rivals like BP have at least tried to move away from fossil fuels) and therefore a poor investment.

It might not seem radical stuff but it could put serious pressure on corporations - afterall they see their main responsibility is to shareholders. and shareholders are predominantly pensions funds. and pension funds are ultimately made up of YOUR money. use it.