Votes will decide on 20 May

The referendum, on 20 May, was secured after 'Yes' vote campaigners collected signatures from 8,500 people, more than 10% of the local electorate.

The next hurdle for pro-mayor campaigners is to secure a 'Yes' vote in the poll.

Meanwhile, Plaid Cymru and independents say they will back a 'No' vote as part of campaigning for the local elections.

Those backing a directly-elected mayor in Ceredigion claim the council, run by a coalition of Independents and Liberal Democrats, is undemocratic.

This is our opportunity to choose policies that are right for us Emyr Hywel

They also oppose plans to build 6,500 new houses in the county.

Though many Plaid Cymru members were active in the campaign for a referendum, the party leadership says they should vote against a mayor, and concentrate on gains in June's local government elections.

Leaders of all the main political parties in Ceredigion are opposed to a new mayor. Plaid Cymru and the Independents say they will be campaigning for a 'no' vote as part of the local council election campaign.

The 'Yes for Mayor' campaign say they have attracted cross-party support

However, 'Yes' campaigners claim they will have support from within many political parties in the referendum.

If people vote yes, it will be the first directly-elected mayor in Wales, with the election probably taking place on 21 October.

Campaigners claim the houses will destroy the local environment and damage the Welsh language. They say too many of the planned properties are executive-type developments, which local people cannot afford.

They have announced support from four prominent local politicians - former Plaid Cymru Mayor of Aberystwyth, Sion Jobbins, former Conservative parliamentary candidate Felix Aubel and Emyr Hywel, the leader of Llais Ceredigion.

A message of support has also been sent to the launch by academic and Labour Party member, Professor Howard Williams.

A 'Yes for Mayor' campaign spokesman said that this showed that support for establishing a mayor cut across political divides.

Speaking at the launch on Monday, Mr Hywel said: "This is our opportunity to choose policies that are right for us, and elect a candidate who is prepared to respond to people's concerns."