Jailing Heathrow 13 poses 'massive threat' to peaceful protest rights

Letter from high-profile signatories including Caroline Lucas and John McDonnell warns prison sentences would be unjust and disproportionate

Jailing the 13 activists who last year chained themselves on Heathrow's northern runway in protest at the airport's expansion would represent a "massive threat" to the right to peaceful protest in the UK, according to John McDonnell and Caroline Lucas.

In a letter to the Guardian, the shadow chancellor and Green party MP, along with the vice-president of the National Union of Students and several prominent environmentalists, warn that prison sentences for the climate campaigners would be unjust and disproportionate.