Green MP Caroline Lucas told the court she felt it was important to protest about fracking to prevent the UK from being locked into using more fossil fuels.
Ms Lucas said: "I'm haunted by the idea that my children and my children's children will turn round to me and say, 'What did you do about this overwhelming threat?'"
Her co-defendants were also cleared of both charges against them. They were Josef Dobraszczyk, 22, from Bristol; Ruth Jarman, 50, from Hook, Hampshire; Sheila Menon, 42, from north east London; and Ruth Potts, 39, from Totnes, Devon.
More top news
A cloudy afternoon for many areas across the UK. The winds also strong with gusts on western coasts of Scotland. Temperatures remain mild.
A girl was told she would never walk again after she fell into a scalding bath as a baby has taken her first steps - after a leg amputation.
Could changes to diet could prevent or even reverse diabetes and help the NHS cut some of the £10 billion annual spend on treatment?