Breaches of electoral law are a matter for the police and the #electioncommission . The candidate's agent has been held to be responsible for a couple of centuries. If the breaches are likely to have affected the result it may go to an election court which may impose criminal penalties and set the result aside - although the latter event is rare! National parties are more difficult to deal with although the #conservatives were in trouble after #ukgeneralelection2015 .