The ESB group of unions has said its position and that of the company's management are "very far apart" after talks aimed at averting threatened strike action ended last night.

ESB management and unions were in talks to discuss issues regarding the company’s pension scheme.

Strike notice is to be served at 2pm today and industrial action will begin at 8am on Monday December 16th unless the dispute is resolved.

The dispute centres on claims by union members that the company's changes to its pension plan means workers are carrying a risk of €1.7 billion. The group's general secretary Brendan Ogle has said they are "not willing to wait for the money to run out".

Speaking to the Irish Times after the talks with the company’s senior management, Mr Ogle said there had been “robust exchanges” and that the meeting had been “very very difficult”.

The ESB released a statement after the talks describing the dialogue as “an open and frank exchange of views” but said “significant differences remain between the parties”.

“Both parties have agreed to engage in intensive dialogue focused on addressing these differences,” the statement added.

Talks between the two sides are set to continue over the coming days – but Mr Ogle said this would not be conducted in the public domain.

“The dialogue which began today and was very very difficult will continue,” said Mr Ogle.

“The parties are now engaged at the highest level but there is no meeting of minds or position that allows the unions not to serve strike notice so that’s what’s going to happen.

“The dialogue is continuing and will probably intensify. We’re not going into specifics. It’s not that we’ve stopped talking. We’re in constant communication and there will be many meetings and sessions over the coming days. We won’t be announcing them all – this will not be conducted in the public spotlight.

“There is serious talking to be done here to resolve the dispute and prevent the strike and that is now underway. Whether it can prevent the strike or not remains to be seen – the parties are very far apart.”

In the meantime, Mr Ogle said the unions will be putting in place a “dispute’s committee” which will be an “operational group on the ground” of the ESB and will contain no union officials.

This committee will be “engaging with the ESB around the specifics of the dispute and emergency service provision” and will also decide upon the logistics of any industrial action.

“The dispute will continue and any consequent action will continue until our agreements are protected, the pension issue is resolved and the company accept on their annual report the liabilities for the scheme,” added Mr Ogle.

Earlier in the day, the unions sent a memo to the company’s management accusing them of “hiding” and having “exposed staff to public attack”.

In the memo to ESB management signed by Mr Ogle and individual union representatives, ESB executives are addressed as “the most senior and highly paid management in ESB” and accused of bringing “this once well managed company to an unprecedented industrial relations crisis”.

The memo went on to outline claims that the company failed to honour commitments made by its former chief executive Padraig McManus in the pensions agreement in 2010 “that the proposals of which you now vote do not, in any way, dilute ESB’s commitment to the pension scheme”.

Yesterday’s memo said: “You have broken faith with your staff and exposed them and their representatives to public attack while you – the people directly responsible for this crisis – have hidden away from accountability and scrutiny.”

It went on to address senior executives at the ESB directly and claimed to be “holding you accountable today”.

The memo concluded with the assertion that the unionised staff in ESB “will not be bullied by you any longer”.

"Workers and taxpayers in Ireland have already paid for enough gambling debts brought about by irresponsible behaviour for which nobody has been properly held to account. We will not pay for your gambling debts and we hold you accountable for this crisis.

“You have a short time to return to the type of stable, sober and responsible management which, allied with the efforts of staff, built a strong company that lasted from 1927 to 2010.

“Your departure from it since is utterly irresponsible, and we call on you to revert to proper management or consider your positions.”

ESB’s unions last week voted in favour of striking as management and workers remained at odds over the scheme’s solvency, with staff claiming that the pension pot is €1.7 billion short while the company says that this is not the case.

The row over the pension scheme dates back to 2011 when the unions and company implemented a plan designed to plug a €2 billion gap in the fund identified by actuaries.