The two south and east London clubs face off for the first time in 14 years on Saturday, with tension running high ahead of a ferocious Championship encounter at the Den.
Metropolitan Police have been granted special powers to tackle potential violence, with only 1,774 tickets allocated to West Ham supporters for the fixture.
A dedicated walkway linking South Bermondsey station to the away end has been described as a cooling measure designed to keep opposing fans separated on matchday.
This will mark the 100th competitive meeting between the clubs, if discontinued and minor tournaments are included, a grim milestone that few neutrals will be celebrating.
The rivalry traces its roots beyond football, dating back to when both clubs were formed by rival shipbuilding firms at docks on the Isle of Dogs in east London.
The most disturbing recent flashpoint came in August 2009, when a 44-year-old man was stabbed in the chest as trouble raged outside Upton Park during a League Cup second-round tie.
Play was suspended briefly during that 2009 match when home supporters invaded the pitch after a West Ham goal, with riot police struggling to maintain order inside the ground.
In March 2004, police horses were deployed on the pitch when West Ham fans rioted and ripped up seats during a 4-1 defeat at the Den, forcing restrictions on where away supporters could sit for the return fixture eight months later.
A Millwall fan, Ian Pratt, died after a clash with West Ham fans at New Cross station in 1976, a tragedy that underlines why glorifying this rivalry remains deeply irresponsible.
The clubs have only shared top-flight football once since the Second World War, in the 1988-89 season, when Millwall stayed up but West Ham were relegated, which is typically the condition that brings these sides together.
Millwall have not lost at home to West Ham since 1988, recording five unbeaten home results in that run, giving Alex Neil’s side a psychological edge heading into Saturday’s encounter.
West Ham, managed after Alan Pardew led them back to the Premier League in 2005, arrive in strong form, sitting top of the Championship following a crushing 6-0 victory over Wrexham last weekend.
Millwall came close to winning automatic promotion last season but have been hampered by injuries and sit 10th following an inconsistent start to the current campaign.
The irregularity of the fixture adds to its strange mystique, with the game occurring only 18 times in the league since the Second World War, making each meeting feel loaded with history and edge.
Logic suggests West Ham should win, but as anyone familiar with this fixture knows, logic tends to count for very little once the game at the Den actually begins.