Welsh Labour have retracted social media posts after a formal legal letter was issued by Reform UK.

The posts implied Reform’s Caerphilly candidate, Llŷr Powell, had links to Vladimir Putin – an accusation the party firmly denies. They also referred to bribes taken by a former Reform leader.

Newyddion S4C has been told the letter was sent under the Defamation Act 2013 and the Representation of the People Act 1983.

The Defamation Act protects individuals from false statements that damage their reputation, while the Representation of the People Act sets strict rules on false claims during election campaigns.

Powell has come under scrutiny from Welsh Labour for having worked as Nathan Gill’s constituency caseworker while he was a Member of the European Parliament although Reform say his employment ended before the offences took place.

Gill, the former leader of Reform UK in Wales, admitted to taking bribes to promote pro-Russian positions while serving as an MEP.

The 52-year-old from Llangefni pleaded guilty to eight counts of bribery between December 2018 and July 2019.

Reform UK say Welsh Labour have “lost their grip, lost the Welsh people, and lost the argument and they won’t engage in “gutter politics”.

The Meta Ad Library, which documents social media adverts, showed Labour had also paid for similar adverts to the now-deleted social media posts. The library showed the adverts were now inactive.

A Welsh Labour spokesperson said: “Whilst we have removed the social media posts on request from Reform UK, questions remain as to why Reform UK chose a spokesperson for Russia to be their Welsh leader.

“Welsh Labour will not stop asking these questions.”

It comes as the Caerphilly by-election approaches with polling day on 23 October with the candidates list as follows: Richard Tunnicliffe (Welsh Labour), Lindsay Whittle (Plaid Cymru), Gareth Potter (Welsh Conservatives), Llŷr Powell (Reform UK), Gareth Hughes (Wales Green Party) Steven Aicheler (Welsh Liberal Democrats), Roger Quilliam (UKIP), Anthony Cook (Gwlad).