Conall McDevitt has vowed that he is finished with politics – just hours after the SDLP's deputy leader said she hoped he would consider a return to public life in the future.
The South Belfast MLA quit after admitting he had broken Assembly rules by not declaring £6,750 in payments from his former public relations company.
Mr McDevitt said he had fallen below the standards expected of someone in public life. The 41-year-old's departure has been seen as a major blow for the SDLP.
Yesterday its deputy leader Dolores Kelly said she hoped he would "re-engage" with the party and consider being a public representative again in the future.
However, Mr McDevitt later said he would not be returning.
Writing on Twitter, he said: "Thanks everyone for your kind words and messages. Just want to make clear that I will not be returning to public life in the future."
Mr McDevitt quit on Wednesday over the £6,750 payment he received in 2010 from his PR company, Weber Shandwick, which had not been declared in the Register of Members' interests.
He had already been under pressure after it emerged his wife Joanne Murphy received a £16,000 Policing Board allowance for research work. Ms Murphy's company, JM Consulting, was also paid £14,000 for research and secretarial work from Mr McDevitt's Assembly expenses. Mr McDevitt insisted he had done nothing wrong in respect of these two payments and that his wife had not benefited.
However, he admitted the failure to declare the £6,750 payment from his former employers had been a serious oversight. The SDLP must now decide who to fill the vacant South Belfast seat, with ex-UTV journalist Fearghal McKinney and Claire Hanna the early contenders.
Ms Hanna said she had been "really upset" by Mr McDevitt's resignation after it emerged that she had sent a letter to 300 SDLP members last month expressing interest in taking a South Belfast seat, which she said yesterday was only if Alasdair McDonnell stepped down from the Assembly over double-jobbing.
There was also support from Upper Bann MLA Ms Kelly, who said she hoped he would not leave public life for good.
Former party leader Mark Durkan said: "He is a huge talent, he has paid more than his pound of flesh for his transgressions."
DUP MLA Edwin Poots wrote on his Twitter account: "I enjoyed scrapping with Conall, he was an able opponent."