A Metropolitan Police spokesman said the arrests were made over alleged public order offences.
Six males were arrested during the game at Millwall in relation to a banner being unfurled at the game. They remain in custody at this time."
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Warm and humid over the next few days with rain at times in the north.
Warm temperatures will return to parts of the UK this week, hitting highs not seen since mid-July.
British runner Sir Mo Farah has completed his final track race in Great Britain by winning the 3000m at the Birmingham Grand Prix.