Historic castle redevelopment to cost over £55m

Anthony Lewis, Local Democracy Reporter

Plans to redevelop an historic castle into a culture and heritage centre are currently estimated to cost over £55m.

The cost of the redevelopment of the entire Cyfarthfa Castle building is currently estimated to be in excess of £55m, a council report says.

The report for Merthyr Tydfil Council’s Thriving scrutiny committee says that due to funding constraints, a phased approach to the capital project has been proposed.

The cost of the first phase, which would develop around 55% of the entire building focussed at the oldest (mansion) side, is estimated to be around £32m.

Pledges of around £700,000 for the capital project have already been confirmed to The Cyfarthfa Foundation from private charitable trusts.

Alongside development of the long-term site plans, a programme of conservation works is currently being delivered on site in 2026/27 led by the council.

This is preserving the fabric of the building and helping lay the foundation for the proposed redevelopment.

In February 2026, the foundation and the council submitted an application to the National Lottery Heritage Fund.

The application is currently under consideration by the National Lottery Board but if successful it would unlock around £10m of investment for realisation of the phase one capital project.

Officers are currently working with the National Lottery and an outcome is expected during July 2026.

The foundation’s work has focused on two main areas.

The first being to take forward the capital project for the redevelopment of the Cyfarthfa site as a culture and heritage visitor destination of national significance.

The second has been to “deliver meaningful community development and engagement through activation of the existing site to cultivate audiences, increase footfall and strengthen connections to Cyfarthfa via new culture, leisure, recreation and education opportunities.”

In September 2025, the foundation completed work on a master plan for Cyfarthfa Castle.

The council report says this work recognises the “complex and costly nature of developing the castle building, identifying the key issues to be addressed.”

These issues include the scale of the building combined with its location in a listed park with complex ecology and archaeology making it a challenging building to manage and repair.

Another issue is making the building watertight and bringing over 3,000 square metres of empty Grade I listed building back into use.

Other issues include protecting the existing museum collection, designing interventions to improve ongoing maintenance, removing barriers to access for those with access needs and making the site more inclusive as well as improving the thermal performance to reduce energy consumption and associated running costs.

Long-term financial viability

The report says that for long-term financial viability and the cultural and economic catalyst that Merthyr Tydfil and surrounding area needs, they must build on the successful delivery of the current museum team to create:

Outstanding, environmentally controlled museum spaces with a dedicated temporary gallery suitable for national and international tours to attract new and repeat visitors from across the UK and beyond.

Space to bring the archive collection back to the castle, so that there is not a separation between the collection and the museum. This could include public access / visibility of the archive collection.

Outstanding education facilities, including stores and lunch spaces, to encourage a wider reach to schools – these facilities will also be heavily used in holidays and weekends for family activities and adult learning.

A destination place to eat and drink and new commercial facilities to encourage new and repeat visitors, as well as generating income and supporting sustainability.

The report says that the master plan responds to these needs through the creation of increased enhanced display space, improved building accessibility, dedicated collection management facilities, new public and commercial facilities, bespoke education spaces, enhanced hospitality offers and multi-purpose spaces to accommodate enhanced community uses.

The Cyfarthfa Foundation was created in 2021 following the recommendation of the ‘Crucible’ report.

It recommended that the charitable foundation should work with Merthyr Tydfil Council and others to develop and realise the development of the castle and wider estate as a national centre for industrial heritage and as an anchor project in developing the tourist potential of the south Wales valleys.

A condition survey in October 2022 commissioned by the council highlighted the repair work required to safeguard the future of Cyfarthfa Castle.

In November 2023, Merthyr Tydfil Council approved a recommendation that the heritage assets at Cyfarthfa be transferred to the foundation on a long lease for their management and development, at a future point to be determined.

Anchor site

A bid was submitted to Welsh Government for Cyfarthfa to be anchor site for the National Contemporary Art Gallery for Wales.

In July 2024 the Welsh Government announced that, for financial reasons, the National Contemporary Art Gallery for Wales anchor site project would not proceed.

In February 2025 an expression of interest was submitted to National Lottery Heritage Fund outlining a £10m plus grant application for the first phase capital redevelopment of the castle building.

This was taken forward to a full development stage application in March 2025.

In July 2025, a £4.5m package of pre-development works was confirmed to address the most urgent areas of deterioration and to lay foundations for future capital development with £2.25m from Welsh Government (via Cadw) and a further £2.25m plus of funding from Merthyr Tydfil Council

This included conservation works to the castle roof and windows and installation of new drainage infrastructure across the site to improve long-term water management.

In January 2024, the foundation and the council formed the Cyfarthfa Bicentenary Working Group with the intention of delivering a year-long campaign of celebratory events and activities that would mark the 200th anniversary of Cyfarthfa Castle.

During the last five years (since 2021) the average annual visitor footfall to Cyfarthfa Castle Museum and Art Gallery has been around 37,000.