Oxford United's new manager Darren Patterson had been Smith's No 2 this season after promotion from youth-team coach in March.
He was briefly manager 20 months ago for just three matches but had to move aside following the club's takeover by Nick Merry and Jim Smith, who arrived as a package, with Smith immediately taking charge on the field.
Patterson's main target will be to try to get the team back winning again to try to reach the play-offs. But after a run in which they have taken just 16 points from the last 45 available, that will take some doing. The U's are already nine points adrift of the play-off positions.
The announcement of the managerial changes were made at a press conference at the Kassam Stadium today following Smith's return from a brief break away.
Fans have been increasingly calling for Smith to go, and last week's 5-0 defeat at Rushden appears to have been the final straw.
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