The public body responsible for the redrawing of Wales’ parliamentary constituencies has announced a series of public hearings into their proposals.

With the number of parliamentary seats in Wales set to be reduced from 40 to 32, the Boundary Commission for Wales has been tasked with redrawing the map.

It published its proposals in September – plans which would see significant changes to the constituencies within Caerphilly County Borough.

After the proposals were released, a consultation period followed. Now, a second consultation is set to be held between January 11 and February 21.

The public hearings, which are part of the second consultation period, will be held across Wales.

Shereen Williams MBE OStJ, the secretary to the Boundary Commission for Wales, said the commission is “likely to make significant changes” to its proposals based on evidence received during the consultation periods.

The constituency changes are set to come into force before the next UK General Election, which is scheduled to take place before December 2024.

These boundary changes are happening across the UK to ensure parliamentary constituencies contain roughly similar size electorates. Due to population changes over the years, these boundaries have been redrawn numerous times in the past.

But while Wales loses seats, England’s number of seats will rise by ten to 543.

The number of seats in Scotland will drop by two to 57, while the number of seats in Northern Ireland (18) will stay the same.

However, these boundary changes will not affect Senedd constituency boundaries, which will remain the same.

What are the current constituencies?

Currently, Caerphilly County Borough is split between two and a half constituencies when it comes to General Elections.

The Caerphilly constituency includes the council wards of: Aber Valley; Bargoed; Bedwas, Trethomas, Machen; Gilfach; Hengoed; Llanbradach; Morgan Jones; Nelson; Penyrheol; St Cattwg; St James; St Martins; Ystrad Mynach.

The Islwyn constituency includes the council wards of: Aberbargoed; Abercarn; Argoed; Blackwood; Cefn Fforest; Crosskeys; Crumlin; Maesycwmmer; Newbridge; Pengam; Penmaen; Pontllanfraith; Risca East; Risca West; Ynysddu.

The Merthyr Tydfil and Rhymney constituency, which is split between the northern part of Caerphilly County Borough and the entirety of Merthyr Tydfil County Borough, includes the Caerphilly Council wards of: Darran Valley; Moriah; New Tredegar; Pontlottyn; Twyn Carno.

What are the new proposals?

Under the new proposals put forward by the Boundary Commission, Caerphilly County Borough would cover four constituencies.

Caerphilly town, Aber Valley and Bedwas, Trethomas, Machen would merge with the current Newport West constituency to create the new ‘Newport West and Caerphilly’ seat.

Meanwhile, Llanbradach, Ystrad Mynach, Hengoed and the St Catwg ward would become part of the Islwyn constituency, which will maintain all of its current territory, apart from Aberbargoed, which alongside Bargoed, Gilfach and the Upper Rhymney Valley, would become part of the new ‘Blaenau Gwent and Rhymney’ constituency.

Elsewhere, Nelson would become part of the new ‘Merthyr Tydfil and Aberdare’ constituency.

The Boundary Commission has said it took geography, such as lakes, rivers and mountains, as well as local authority and council ward boundaries, into account when creating its initial proposals. It also said local ties, such as shared history and culture, were taken into account.

The electorate sizes of each of the proposed new constituencies containing parts of Caerphilly County Borough are as follows:

• Blaenau Gwent and Rhymney – 71,079
• Islwyn – 70,735
• Merthyr Tydfil and Aberdare – 71,281
• Newport West and Caerphilly – 74,349

Caerphilly County Borough Council will be unaffected by these changes, with places like Nelson and Bargoed remaining part of Caerphilly County Borough, despite being moved into other parliamentary constituencies.