Mothballing heritage site Llancaiach Fawr would be “tantamount to cultural vandalism”, senior councillors in Caerphilly have been warned.

Supporters of the museum – a Tudor mansion in Nelson – launched an impassioned resistance at a meeting on Tuesday September 24 against the council’s cost-cutting proposals.

A final decision on the matter is due later today (Wednesday September 25).

Gareth Jones, from the Friends of Llancaiach Fawr group, told the meeting the site was the “jewel in the crown” of the county borough’s cultural offer, and a “Welsh treasure”.

The council has not confirmed what will happen to the site if it is mothballed, and Mr Jones said its loss would be a “betrayal to future generations”.

Union representative Lianne Dallimore told the meeting that cuts to culture were “irrational” and warned against “cultural vandalism”.

Llancaiach Fawr had “survived civil war, two world wars, a depression and recessions” but was now under threat in the hands of Caerphilly County Borough Council, she claimed.

Cllr Lindsay Whittle, who leads the Plaid Cymru opposition group in the council chamber, said the site “hasn’t been properly marketed” by the council.

The council announced its mothballing plan as part of a bid to save £45 million over the next two years, with deputy leader Cllr Jamie Pritchard telling the meeting those savings were required “just to stand still”.

He said it was “only fair” to seek ways of making the subsidised site cheaper to run for the council, given the “extremely challenging” financial outlook.

But Cllr Whittle said the annual subsidy of £485,000 that the council spends on the “vital part of our heritage” at Llancaiach Fawr amounted to around 1% of that overall savings target.

“Is it worth the fuss?” he asked.

Councillors Ceri Wright, Charlotte Bishop, Jan Jones, Ann Gair, Nigel Dix and Elizabeth Aldworth were all among those who spoke supportively of the importance of Llancaiach Fawr.

The committee also heard several complaints the site should have been better marketed and utilised by the council.

Mr Jones raised a claim a private investor had approached the council offering to run the site.

Cllr Sean Morgan, who leads the authority, said it would not be appropriate to comment on potentially confidential matters.

The joint scrutiny committee chairman, Cllr Gary Johnston, asked whether the council had calculated the cost of its mothballing plan – and a response of £30,000, from regeneration services manager Alan Dallimore – raised a few eyebrows.

Cllr Roy Saralis then drew some heckling from the public gallery when he referred to voting to save “bricks and mortar”, compared with “saving lives” on a separate vote to axe the council’s Meals Direct service.

To clarify, the futures of Llancaiach Fawr and Meals Direct are not mutually exclusive, and cabinet members are expected to make separate decisions today (Wednesday September 24).

The committee voted to recommend to the cabinet that it “ask officers to develop a range of further options to make the delivery of Llancaiach Fawr Manor sustainable over the long-term”.