LAbour and Doncaster MP Rosie Winterton will oppose the voting system used in the borough’s mayoral elections.
Miss Winterton announced to her Doncaster Central constituency that she will say no to the alternative vote system in the May 5 referendum.
The Doncaster Central MP and Labour Chief Whip is one of eight MPs who have recently announced they will stand against the plans.
The AV system works differently to first past the post in that voters are asked to rank candidates in terms of preference.
In first past the post voters have one vote and the candidate with the most votes is elected.
When counting the votes for AV, ballot papers are gathered in terms of first preferences.
If a candidate gets more than 50 per cent of the votes then they are the elected member of that constituency.
If no one receives 50 per cent of the vote, the second preference votes for the least successful candidates are redistributed.
This process is repeated until a candidate goes past the 50 per cent threshold to take the seat.