However, sport does not operate in a vacuum. At times, sport becomes entangled with social and political issues, e.g. apartheid in sport, boycotts of sporting events due to political events or issues.
In Scotland, sectarianism in sport is mainly perceived to be a football-related issue, largely between Rangers and Celtic football clubs. However, other clubs are often ascribed allegiances, e.g. in Edinburgh, Heart of Midlothian are perceived by some to be the Protestant team and Hibernian as the Catholic team and similar ascribed allegiances are associated with Dundee United and Dundee. Some also try to attribute such associations to rivalries in England, e.g. Liverpool and Everton.
It is true to say that sectarian incidents which occur in football settings, e.g. at or outside matches, are very visible. Yet while football can provide an avenue for sectarianism or religious intolerance, football or football rivalries are clearly not in themselves necessarily sectarian.
When football first started in Scotland, many clubs emerged from existing social organisations including many of a Protestant nature. For example, the first club in Scotland, Queen's Park, was associated with the Young Mens' Christian Association (YMCA). Other teams were associated with the local church. Similarly the Catholic Young Men's Society supported the foundation of Hibernian FC (Hibs) in Edinburgh and Harp in Dundee.
Finn (1994) suggests that, 'the motivations behind the formation of [Catholic Irish-Scots] clubs were complex. Certainly there was a sense of protection to be gained from having clubs that were within the Irish-Scottish community, especially as many of the clubs of the majority were not exactly welcoming to members from the minority. But the Irish-Scots also saw that through sporting exchanges social prejudices could be broken down … Success by Irish-Scottish clubs would win the respect of the Protestant Scottish majority.'
Celtic FC was one such club. Their stated aims included putting the gate money to charitable use to alleviate poverty amongst the Irish-Scots community in Glasgow. The name Celtic referred to the shared Celtic heritage of the Scottish and Irish communities and Celtic's first strip displayed a Celtic cross emblem. Other clubs also had a reference to this heritage as part of their team identity, e.g. the colour of strip or the incorporation of the harp in their logo. Dundee Harp no longer exist and Hibernian have dropped the harp from their logo, however, both Hibs and Celtic continue to play in green strips. These colours themselves are sometimes cited as a prompt for sectarianism, however, it is not the colour but what is associated with it which can lead to sectarian behaviour.
In Ireland (Northern Ireland and the Republic) colours can be a very emotive issue, with certain colours being perceived to be related to one or other side of the political and religious sectarian divide. In Scotland the perception of these colours has to some extent been imported from Ireland, despite the fact that the political divide does not actually exist and the religious divide is much less obvious.
Whilst many clubs in Scotland started with links to religious associations, for most clubs these links have lapsed over time, although the associations are still known. For example, Celtic saw itself as a Scottish club with Irish roots and Rangers saw itself as a Scots Protestant club. As a club, Celtic has long had a recruitment policy open to players of all religious backgrounds while remaining proud of its Irish connections; for example, the Irish tricolour is flown on match days at its stadium leading to the perception that it is a 'Catholic Irish club'. Rangers, with a Protestant-only recruitment policy until near the end of the 20th Century, was perceived by itself and others to be a 'Scots Protestant club'.
Yet there are many supporters of Celtic who are not Catholics and there are many supporters of Rangers who are not Protestant. Indeed, both clubs have substantial groups of supporters drawn from the City's Muslim communities and many supporters of both clubs do not practise a religion at all.
Sectarian incidents do occur in the context of football, and in particular in the context of 'Old Firm' (Celtic v. Rangers) matches. This can range from chants and songs to the use of flags (including those of the paramilitary groups in Northern Ireland), to violence, all of which are perceived to be or are sectarian. Links may also occur with certain forms of nationalism often expressed through the display of Union flags and (Irish) tricolours.  Current and historical issues and events related to the conflict in Northern Ireland may also impact on sectarian attitudes and behaviour at football grounds.  All these elements need consideration when analysing why and how sectarianism is linked to the sport.
There have been a number of requests for Celtic and Rangers to take measures to tackle sectarianism within the clubs, their grounds and among their supporters. Responses have ranged from reprimanding people found to be saying sectarian things within the grounds to people who are convicted of sectarian violence having their season tickets withdrawn. There have also been measures taken by Glasgow City Council to prevent street traders outside the stadiums where Celtic and Rangers play from selling goods which might be perceived to be sectarian, e.g. flags.
Both Celtic and Rangers have education programmes to combat sectarianism. Celtic's Social Charter declares that:
Celtic’s Charter aims for the organisation to be  an inclusive organisation and open to all regardless of age, sex, race, religion or disability.
This is further reinforced by the claim that Celtic will 'act against racism or sectarianism in any form and will not tolerate actions and language that seek to promote racism and sectarianism.  Celtic’s Bhoys Against Bigotry which was launched in 1996, later becoming Youth Against Bigotry was set up to educate young people to develop respect for all in relation to ethnicity, colour and religion and beliefs.
Rangers appeals to supporters and players to adhere to the motto of the club: 'Ready'.
Ranger’s ‘Pride over Prejudice’ programme has a 10 point Action Plan which includes action such as making public address announcements at every home game condemning racism and sectarianism, taking disciplinary action against fans, players and staff whose sectarian and racist behaviour brings the Club into disrepute and utilising their Study Support Centre and Community Football programmes to deliver positive messages to children of all denominations.
Enforcement of these policies can be difficult on the stands. However, the clubs have consistently sent strong messages that sectarianism is not acceptable and this should impact on the supporters. There is evidence of limited success whereby sectarian songs and chants have been heard less at home games and tend now only to be heard at Old Firm away fixtures, where cameras are unable to pick out offenders and identifying them is therefore more difficult.
The Scottish Executive has issued a strategy for tackling sectarianism in football. The publication ‘Calling Full-time on Sectarianism’.  There are eight action areas including the setting up of a new body to focus effort, develop and deliver activities tackle sectarianism associated with Scottish football.  The Scottish Executive’s Action on Sectarianism site provides more information about work being undertaken to tackle sectarianism within sport,
Tackling sectarianism means all of us taking action and working in partnership.  A historic occasion was marked when Scotland’s religious leaders, such as Cardinal Keith O’Brien and Church of Scotland Moderator Alan McDonald, joined representatives from the Jewish, Muslim, Hindu and Sikh communities and First Minister Jack McConnell to see first hand how football clubs are working to tackle sectarianism.