The Wales COVID-19 inquiry special purpose committee was set up by politicians in Cardiff Bay to fill any “gaps” in the UK-wide inquiry’s scrutiny of decisions made by the Welsh government.
Tom Giffard said he had resigned as co-chair of the committee after Welsh Labour members voted against an amendment which would have allowed witnesses, including ministers, to give evidence under oath.
Fellow Conservative Senedd member Sam Rowlands has also stepped down from the committee.
In a statement, Mr Giffard said that he had resigned “with a heavy heart” and that the Welsh Conservatives would “no longer engage with the committee”.
“Families who lost loved ones deserve honest answers, yet Labour’s decision to block oaths being taken undermines any chance of getting to the truth,” he said.
“Without the safeguard of requiring witnesses to speak under oath, this committee has become a pointless talking shop.”
The UK COVID Inquiry has heard evidence from politicians and experts in Wales, including Mark Drakeford, who was first minister during the pandemic.
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Families of those who died during the pandemic have called for Wales to have its own inquiry, as is the case in Scotland.
But the Welsh government has rejected calls for the country to have its own independent inquiry into the COVID response.
Mr Giffard said the Welsh Conservatives would continue to call for an independent probe into the pandemic in Wales.
Sky News has asked Welsh Labour for its response.