The Electoral Commission halted the campaign by the Green Party to persuade Sussex University students to sign over their votes to a proxy.
The watchdog’s intervention was reported by a political rival, the Liberal Democrat commentator and public relations expert Mark Pack, on his blog.
He said that he had previously highlighted “complaints about the Green Party’s proxy voting campaign in Brighton, handing out forms pre-completed with the names of Green Party activists in apparent breach of the Electoral Commission Code of Conduct’s provisions designed to avoid proxy voting fraud”.
Mr Pack said: “The Electoral Commission hasn’t hedged its words when I asked them for a reaction.”
He quoted the Electoral Commission as saying: “Our non-statutory code of conduct says voters should not be encouraged to appoint a campaigner as a proxy to minimise the risk of suspicions that campaigners are placing undue pressure on voters.
“We have been in contact with the Green Party to make clear that this is not acceptable campaigning behaviour.
“They have now stopped these activities and we will continue monitoring to make sure there is no repeat.”