Reuben Page from the Environment Agency says that the oxygen levels in the canal are now back to normal.
The oxygen levels were affected by the recent warm weather, which the Environment Agency says usually only affects still water.
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He said he will stand for leader again if a fresh contest is held amid growing calls for him to stand down within the party.
Labour's deputy leader Tom Watson was enjoying a silent disco at Glastonbury Festival as the party leadership became embroiled in civil war.