UPDATE 6.21pm: Claims that the AM for Monmouth was drunk at a debate about mental health have reportedly been denied by politician.

Nick Ramsay has denied that he was drunk at the debate on Tuesday, reports said last night.

Jonathan Williams, the Cardiff man who raised the complaint with Rosemary Butler, said the response to his letter “has been exactly as I expected. No one will take this matter seriously because politics is a cosy club.

“All they are interested in is protecting their collective reputations. It's mucky and makes me wonder why I bothered writing in the first place.”

UPDATE 1.46pm: A Welsh Tory spokesman has stated that Nick Ramsay was making valid contributions to the debate where a member of the public has claimed that the Monmouth Tory AM appeared drunk.

In a statement the spokesman said: "Nick Ramsay was making valid contributions in an important debate on mental health.

"He agrees that all correspondence from the public should be treated with the utmost importance – and will speak to the Presiding Officer accordingly."

UPDATE 1.22pm: Assembly presiding officers are set to investigate the circumstances around a complaint that claimed that Nick Ramsay was drunk during an Assembly debate.

An Assembly spokesman has confirmed that Newport West AM and Assembly presiding officer Rosemary Butler has recieved a complaint relating to the behaviour of the Monmouth AM.

He said: “The Presiding Officer has received a letter of complaint relating to the behaviour of an individual Assembly Member in the Plenary session on 10 June.

“Regulation of Plenary proceedings is a matter for the Presiding Officers. They will be looking into the circumstances thoroughly and properly over the coming days.

“The rules of debate are governed by Standing Order 13 and the Assembly Members’ Code of Conduct sets out the standard of behaviour expected from Members during Assembly business. Members must at all times in their conduct promote respect for the Assembly and extend respect and courtesy to other Members.”

The code of conduct can be found here.

12.49pm: A MEMBER of the public has complained to the Assembly's presiding officer that the Tory AM for Monmouth appeared to be drunk during a debate on mental health on Tuesday.

The complaint alleges that Nick Ramsay’s “contributions were slurred, incoherent and insolent” on more than one occasion.

Plaid Cymru says it expects the matter to be fully investigated.

In an email written to the presiding officer Rosemary Butler the member of the public claimed: “The Assembly member for Monmouth is in a privileged position to serve his constituents, but to appear in the chamber unsteady on his feet and clearly drunk is unforgivable.”

Mr Ramsay had made interventions during a debate on mental health during a speech by the health minister Mark Drakeford.

A worker in Cardiff AM Julie Morgan’s office confirmed reports that the complaint about Mr Ramsay had reached her office and was passed on to the presiding officer by the AM.

The worker was keen to stress that Ms Morgan has herself not made a complaint and passing it on was a formality.

A Plaid spokeswoman said: “Any complaint by a member of the public about the conduct of Assembly Members should be taken seriously, and we expect the presiding officer to investigate this matter fully.”

The Argus has made requests for a response from Nick Ramsay, the Welsh Conservatives and the Assembly this morning but as yet has received no reply.

You can watch Mr Ramsay’s contributions to the debate in this video – Mr Ramsay’s contributions start at around seven minutes 20 seconds in.