I recommend that if your union does make donations to the Labour Party it stops doing so until such a time as the Labour Party rediscovers the benefits and need for public services

John Marek, AM

The dispute arose on Thursday on the eve of Welsh Labour's annual conference in Llandudno.

In the letter, Wrexham AM Dr Marek said: "I recommend that if your union does make donations to the Labour Party it stops doing so until such a time as the Labour Party rediscovers the benefits and need for public services.

"What amazes me is that trade unions continue to give donations to the Labour Party in the belief it represents their interests.

Dr Marek: Public services undervalued

"In the last few years this is patently not so."

The statement has been widely backed by union officials.

Billy Hayes, General Secretary of the Communication Workers Union said: "Not one penny will go to any organisation unless it guarantees to support our call for a publicly-owned, publicly-funded Post Office.

"We only have so much money and we want to deploy that effectively. We will be asking similar questions of all our contractors."

Defending his comments in the letter Dr Marek said: "All governments get remote, they always think they know best - and we're in such a position now.

"Of course the Labour party and trade unions will continue to work together - but at the moment trade unions are not being listened to."

Dr Marek also said he was sure Labour would rediscover the need for public services "eventually".

I welcome John Marek's honesty, in the hope that we can now have an open debate about this issue

Ian Titherington, Undeb

But he said a union could hasten that process by withdrawing their donations.

Dr Marek also raised concerns over plans by postal regulator Postcomm to give rival firms the chance to bid for post office business.

The senior politician's criticisms have been welcomed by Plaid Cymru's trade union section, Undeb.

Undeb Secretary Ian Titherington said: "The primary role of every trade union is to represent its members and not to bankroll the Labour Party.

"I welcome John Marek's honesty, in the hope that we can now have an open debate about this issue."