"Ballot papers are not binned, theyre held by elected MPs."
Under the Representation of the People Act 1983 the Returning Officer, usually a senior official of the local council, has to ensure that all ballot papers, counterfoils and the polling clerks' marked copies of the electoral register are safely deposited with the Clerk of the Crown in Chancery (a senior officer of the Lord Chancellor's Department). This is so that if any corrupt or illegal election practices are reported the appropriate documents are available for inspection. All such documents are supposed to be officially sealed so that there is no chance of interference by any party and, according to the 1983 act, the seal can only be broken by the order of the High Court or Parliament itself.
In practice ballot papers are simply bundled-up into paper sacks and transported to a warehouse in Hayes, Middlesex, where they are stored for the statutory period of one year and one day.