They claim they were assured across the last five months that their UEFA Club Licence application would be granted, despite a rule against clubs less than three years old competing in European competitions.

The FAI released a statement on Wednesday saying they were "looking into" a licencing matter after receiving a letter from St Patrick’s Athletic. The Dublin club are set to take Waterford's place in the Europa League qualifying rounds as the next best finisher in last year's League of Ireland.

Then, yesterday, another FAI statement revealed that they had been notified by UEFA that Waterford's "exception request" to the three-year rule had been rejected and, therefore, would not be eligible to compete in Europe.

A similar exception was made by UEFA for Sporting Fingal in 2010, although Derry City were rejected in similar circumstances in 2012.

Waterford will lose out on at least €240,000 in prize money. The club say they had budgeted for the qualification money due and had entered into "substantial commercial agreements and invested heavily again into the team" on that basis.

Chairman and owner Lee Power said in a statement released by the club:

"This will now have a serious financial impact on the club going forward."

Power completed his takeover of the club in 2016, which involved setting up the club as a new entity the following year.

"Everyone at Waterford FC are deeply shocked and saddened at the news that we have been expelled from playing in the Europa League this season," he said in the statement.

"We feel we have been totally misled by the FAI and were given assurances throughout this five-month process by them that the licence would be granted. We also had club visits by UEFA Delegates during this period of which no issues were raised.

"As a club, we entered into substantial commercial agreements and invested heavily again into the team and also budgeted for the qualification money due in November. This will now have a serious financial impact on the club going forward.

"The circumstances to which this decision has been made and the events over the last week are unclear and dubious, bearing in mind representations made to us and assurances given.

"We will be asking for a full investigation into the FAI handling of this matter.

"I have instructed my UK Lawyers to lodge an immediate appeal with UEFA and will pursue any legal avenue we have with regards to compensation and/or any wrong doing against a number of parties.

"Finally, I must mention the people who matter the most – the supporters - who have supported this club through thick and thin and have been badly let down by the people in Ireland governing this process."

The FAI have been contacted for comment.