TROUBLE-plagued Attorney-General Michael Atkinson has fallen on his sword to make way for fresh blood in a new Labor ministry.
He will remain in Parliament until the next election in 2014.
Mr Atkinson said that it would be irresponsible, given the Government's majority of one, to create a by-election in those circumstances.
Mr Atkinson also praised Premier Mike Rann, saying he "prevailed against all the odds and he can stay as Premier for as long as he likes".
"I believe there should be renewal," he said.
" I have had 20 years in Parliament.
"I think there ought to be renewal in the ministry. I think there are talented people on the Labor backbench who deserve a go.
"I don't think we want all the ministry leaving in a bunch about 2014 and so it's important that renewal be staged."
Mr Atkinson said one of the factors in the decision had been wanting to watch his son Johnno play soccer for Woodville-Belgrade.
"He was supposed to play his first game last night at 7pm and like so many times in my time in Parliament I wasn't there," he said. " I am pretty disappointed about that.
"So I resolved that every time Johnno walks on the pitch this year his dad is going to be there even if it embarrasses the hell out of him."
Mr Atkinson said no one had suggested he stand aside. He had started phoning people about it yesterday and had confirmed the decision this morning.
He left at a time when the crime rate was down 33 per cent or 38 per cent depending which measure you use.
"Over eight years we have brought the criminal justice system in SA much closer to society's values," Mr Atkinson said.
Mr Atkinson, who was first elected to Parliament in 1989, made the shock announcement outside a Prospect church just after 10.45am today.
The 51-year-old has been a lightning rod for most of the major problems to have hit Labor in the past two terms.
He has been dogged by a string of controversies - think internet censorship, stashed cash, Ashbourne-Clarke and the senior magistrate defamation case.
He also has attracted national criticism over his refusal to allow an R18+ rating for video games.
His humiliating backflip over internet censorship laws on the night of Februrary 2 came after a furious reaction on AdelaideNow to The Advertiser's exclusive report on the new law.
Earlier that day, Mr Atkinson tried to defend the new law on radio.
He said the new law was necessary because people such as Aaron Fornarino, who regularly posts comments on AdelaideNow, were Liberal Party plants.
But embarrassingly for Mr Atkinson, Mr Fornarino does exist. He lives in a flat on Port Rd, 500m from Mr Atkinson's electorate office.
After the backdown was revealed on AdelaideNow, Premier Mike Rann posted three Twitter messages: "AG has listened. So no debate will be stifled. No political censorship of blogs or online comments whether named or anon."
"All MPs and all parties voted for Electoral law. Hope Libs, Greens, Family First, Independents etc will join us to support repeal."
The attorney-general also took a leading role in the formulation of the Rann Government's controversial anti-bikie laws.