Shamed former SNP finance secretary Derek Mackay has insisted he is “contributing to society” three years after quitting the government after sending text messages to a teenage boy.

Mr Mackay, who took £130,000 of public money in wages and resettlement grants after quitting his top job, was spotted at the All-Energy Conference in Glasgow.

He resigned from the cabinet on the eve of the budget in February 2020 after the Scottish Sun reported he had pestered a 16-year-old schoolboy with unwanted texts.

Mr Mackay, who had been tipped as a future First Minister, said he took “full responsibility” for his actions and he had “behaved foolishly”.

The former Renfrewshire MSP has set up a consultancy firm Lochan Associates after leaving office, when he continued to be paid as an MSP until the 2022 Holyrood election.

Read more: Disgraced Derek Mackay flees the media through basement after return to Holyrood

In September last year, the disgraced former SNP minister evaded the media after giving evidence to a Holyrood committee no the ferries scandal.

Speaking at the SEC, Mr Mackay told The Sun that he acknowledged “discomfort” may have been caused by what happened.

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He said: "I think it is clear I resigned, left public office, and now getting on with my life.

"I have apologised before and I apologise again. I apologised publicly.”

Asked why he was at the event, Mr Mackay said: "Because I am working, contributing to society, and this is about renewables, that’s why I’m here today.

"I’ve apologised for any discomfort that caused and I’m just trying to get on with my life like everyone else is.”

Read more: Disgraced ex-SNP minister Derek Mackay sets up consultancy

The father-of-two, who was 42 at the time of his resignation, said: “I apologise unreservedly to the individual involved and his family.

"I spoke last night with the first minister and tendered my resignation with immediate effect.

"Serving in government has been a huge privilege and I am sorry to have let colleagues and supporters down."

Despite never being seen at the parliament again, Mr Mackay continued to draw a basic MSP’s salary of £64,470 while sitting as an independent.

He also received an automatic grant of £11,945 – the equivalent of three months’ Cabinet salary - for loss of ministerial office.

After leaving parliament in spring 2021, Mr Mackay also received an automatic resettlement grant of £53,725 because he had served 10 years as an MSP.