Section 5 are a football hooligan firm associated with West Bromwich Albion F.C. Whilst Albion have had several other firms since the 1960s, Section 5 is the largest.
Section 5 Wikipedia
Section Five are mainly located in the Smethwick End stand. They are known for their involvement in violent clashes with supporters of rival teams, especially with local clubs Wolverhampton Wanderers, Birmingham City and above all Aston Villa. A history of trouble has also existed with Walsall, Cardiff City, Swansea City, Leeds United, Manchester United, Everton, Nottingham Forest, Derby County, Sheffield United, Coventry City, Stoke City, Bristol City and Burnley.
In 2002, West Bromwich Albion and Wolverhampton Wanderers supporters met up in Amsterdam ahead of the England vs. the Netherlands game. Over 50 men fought in the town centre, a conflict that was captured on CCTV. Footage showed a number of Wolves fans throwing bottles into a pub and waiting outside. West Bromwich Albion then ran out of the pub and attacked the Wolves hooligans.
Also in 2004, West Bromwich Albion's Section 5 met up with Cardiff City's Soul Crew in a massive brawl in Cardiff. As Section 5 was getting an escort to the ground, several men broke through the police line and charged at the Soul Crew.
Albion's promotion-clinching game at home to Bradford City in April 2004 also saw violent incidents and pitch invasions which resulted in a large number of fans receiving banning orders.
On 22 August 2004, up to 80 West Brom and Aston Villa fans fought a pitched battle, with some using baseball bats, wooden posts, bricks, glasses and iron bars, at the Uplands pub, in Handsworth after a game against Aston Villa. Eight people were injured. The organised fight led to the conviction of 60 hooligans (23 from West Brom and 37 from Aston Villa) at Birmingham Crown Court on 5 December 2006. 58 received football banning orders with prison sentences of up to 21 months.
(The name 'Section 5' probably originates from a section of law (possibly the Public Order Act) aimed at football hooliganism / violent behaviour).
This part is incorrect. 'Section 5' is derived from the old Birmingham Road terracing where WBS fans used to stand. It was split into sections, with the number of each area being overhead. Section 5 was in the middle at the rear of the stand and was where all the chanting normally originated which spread across the ground. This was where many if not most of the firm stood with a smaller amount being in the Smethwick end.