CO-OPERATION between the Green Party and Plaid Cymru was on the brink of breakdown yesterday after nationalists were accused of “social media harassment.”

The parties have formed a so-called “anti-austerity alliance” with the SNP and hope to hold the balance of power in Parliament after the general election.

Plaid’s campaign chief Dafydd Wigley has even appealed for Welsh ex-pats in England to vote Green in May.