Seán Conlan’s brief career as a Fine Gael TD has been described as an “unhappy trip” by an observer of the political scene in Monaghan.

“He was a happy country solicitor and a bright fellow from a very good family, from a political dynasty with longevity. Now everything has fallen apart for him,” was the assessment following Conlan’s departure from the party yesterday. “It’s an open secret he’s been an unhappy camper for months now for a variety of reasons.”

He came to public attention last year when a British antiques dealer wrote to the Taoiseach when she could not contact the TD about a €10,000 diamond ring.

Conlan said he and his partner had brought the ring, which was returned, home from the UK for appraisal and accused Mr Kenny of attempting to damage his reputation.

The Employment Appeals Tribunal directed Conlan to pay €25,000 to his former secretarial assistant, who took an unfair dismissal case. He is appealing the judgment.

Last night Conlan said the “only reason” for his resignation was his opposition to the North-South Interconnector and a feeling that “individuals within Fine Gael” were attacking him because of stances he had taken on some issues and how that played out in the media”. He accused “certain members of the media” of aiding those “who wanted to keep me quiet”.

Conlan’s departure from Fine Gael follows that of councillor Hugh McElvaney, his director of elections in 2011, who also cited concerns about the interconnector, which is a major issue in the Border counties.

A cursory statement by Fine Gael made clear the party was not overly concerned about his departure.

Conlan said, as the son of a man who represented the Fine Gael for 49 years in Co Monaghan, “I am not angry but deeply saddened and disappointed by what has been done to the Fine Gael Party by those at the top”.

He said he had warned in the past that those who speak out in Fine Gael “will be punished and this is exactly what I feel has happened to me”.