Former Irish Water managing director John Tierney will walk away from the controversial utility with an estimated €300,000 tax-free retirement lump sum, it has been reported.

Mr Tierney officially retired from Irish Water last month, after three years at the helm of the controversial agency which oversaw the implementation of water charges.

The former Dublin City manager, who worked in local government for 36 years before joining Irish Water, was paid a €200,000 annual salary when he was appointed by the former environment minister Phil Hogan.

As with all senior civil servants and semi-state chiefs, he is entitled to a severance package worth one and-a-half times his salary on retirement, the Sunday Independent reports.

He is also entitled to receive an annual pension payment based on half his salary on retirement. This is also in line with payments received by all civil servants.