Cox was only elected to office last year but she already was considered a rising star in the center-left Labour Party. Her previous career involved working with international charities, and she has been a vocal supporter of refugees including those from majority Muslim nations like Syria. She also frequently called upon Britain to do more to help civilians in Syria.
These positions would certainly put her at odds with many of the supporters of Britain First. The group were formed by former members of the far right British National Party (BNP) in 2011 and have links to Ulster loyalist groups in Northern Ireland. In particular, Britain First campaigns against immigration and multiculturalism. Britain's Muslim community is often a target, although the group specifically denies it is racist.
Although Britain First is far from a major political force in the country – it has entered candidates in a number of different elections but has never won an elected post – the group is extremely active on social media. Often, members will film themselves marching on provocative walks through large Muslim communities. Britain First likes to play on its own religious identity, describing this march and others like them as a "Christian Patrol."
As hard-line as Britain First may seem, it is a frequent target of mockery in the country. For example, party chairman Paul Golding recently contested the London mayoral election. When Labour Party candidate Sadiq Khan, a practicing Muslim, won the election, Golding turned his back the new mayor in a protest many found comical.
Britain First's levels of public support may be relatively low, but the anxiety about immigration the group presents is far more widespread. Next week, Britain will vote on whether to leave the European Union in a referendum. Polls show an increasingly tight race that has taken many by surprise: In particular, voters who favor leaving the E.U. seem to be largely motivated by fears over immigration, rather than the economy. Cox was a vocal supporter of the campaign to remain in Europe, while Britain First supported the campaign to leave it along with the more established United Kingdom Independence Party (UKIP) and some members of the Conservative party.
In the aftermath of Thursday's attack, Britain First released a statement: "This is a terrible day for our democracy and our parliamentary system," group leader Golding said in a video message. "This is a very dark day for our country and our democracy."
Golding sought to dispute the idea that the attacker may have shouted the name of his organization, describing it as "hearsay" and accusing the media of often lying and distorting the facts. He went on to suggest that the attacker may have been referring to the upcoming debate about Britain's membership of the European Union by shouting "it's time to put Britain first."