Nearly half of the councillors in east Suffolk will lose their seats at the next election – as the area’s two main authorities merge into one unit.

Suffolk Coastal and Waveney have agreed on a councillor cull, cutting their total numbers from 90 to 55, saving taxpayers nearly £200,000 a year.

Keeping all the councillors on the new “super council” was never an option with 90 being too unwieldy, but the cut will mean the newly-elected East Suffolk district councillors will have larger ward populations to serve.

Details of how the new council could look have been revealed for the first time in a 137-page document outlining the two council’s proposals for electoral changes.

They started working on the project ahead of the Local Government Boundary Commission for England (LGBCE) because of worries over timescales, afraid the work could not be finished in time for the May 2019 elections when the merger should be complete.

Boundary commission officials will announce their version of the new arrangements, having examined the councils’ proposals, in July ready for consultation.

In a report, Waveney councillor Mark Bee and Suffolk Coastal councillor Geoff Holdcroft, of the members working group, explained the complexities of agreeing new wards where population forecasts have had to be made and some places will share councillors with neighbours in future.

They said: “One of the first exercises was to agree a forecast of the electorate.

“The LGBCE requirement was that data for the review should be based on a five-year housing forecast expected in each polling district area by 2023.

“Nothing beyond this period can be considered for a review. Furthermore, this data had to be submitted by January 31. This deadline was met and the information has been accepted by the LGBCE.”

Each councillor will represent around 3,300 voters under the changes.

The new warding proposal would create eight single member wards, 16 two-member and five three-member.

The council said its proposals reflected local views “working with the geographical constraints of the nature of the district, in terms of boundaries and pockets of population”.