He announced the news on the pitch at Grimsby Town after his side had drawn 1-1.
But it was not enough to prevent Todd leaving who said the decision to leave had been made during the week after meeting with chairman Raj Singh.
Todd said assistant manager Dean Windass will not be his replacement but Singh must act fast as Darlington have a home game on Tuesday.
Todd was appointed during May with and he had to rebuild a squad torn apart by administration which had left Darlington with only two senior pros - Steve Foster and Ian Miller.
The manager has been able to sign 20 players, including seven loans, but Todd's team are currently bottom of League Two with only two points from nine games – the worst start to a season in the
“I didn't prompt it, I think results prompted it – that's the business we are in. Whether the decision has been hasty or not I don't know.Colin Todd
“I'm leaving the football club now, I don't know who will be in charge for Tuesday's game,” said Todd on the Blundell Park pitch.
“The decision was made during the week, by mutual consent.
“I didn't prompt it, I think results prompted it – that's the business we are in. Whether the decision has been hasty or not I don't know."
"At certain levels you're dictated by results, the time factor sometimes isn't long enough but you have to take the rough with the smooth.
"I think the chairman should have been here to address the situation. I've had the players all in together and nobody had any idea, not even my staff [that I was going]."
Todd's appointment represented his return to English football having been working in Denmark as manager of Randers.
Born into a mining family in Chester-le-Street, he began his playing career at Sunderland where his cultured displays as a central defender caught the attention of Derby manager Brian Clough who
paid £175,000 for his services.
An eight-year spell at the Baseball Ground earned Todd 27 England caps and two league titles before he joined Everton and Birmingham City before linking up again with Clough at Nottingham Forest.
After cutting his managerial teeth at Middlesbrough - presiding over one of the club's most troubled periods, when the club went into liquidation in 1986 - Todd moved to Bolton Wanderers where he
forged a reputation for using his extensive contacts in Europe to unearth a series of bargain buys.
The capture of goalkeeper Jussi Jaaskelainen for a fee of £300,000, who has since gone on to make almost 400 appearances at the Reebok, was one of a host of unheralded foreign imports who became
mainstays of the Bolton side.
Todd was also responsible for bringing current Barcelona striker Eidur Gudjohnsen to England along with Claus Jensen, Ricardo Gardner and Per Frandsen.
He has also previously managed Swindon and Bradford City.