Kim Leadbeater, the MP for Batley and Spen and sister of the late Jo Cox, says that political division in the UK is probably worse now than it was in the run-up to the 2016 Brexit referendum — and that MPs face more severe abuse today than when her sister was killed.

The statement comes on 16 June 2026, the tenth anniversary of Jo Cox's murder. Cox was shot and stabbed by neo-Nazi Thomas Mair in her Batley and Spen constituency on 16 June 2016, according to the BBC. The timing is not coincidental: the killing occurred just one week before the Brexit vote that would split British politics for the following decade.

Leadbeater inherited both the parliamentary seat and what is arguably the most charged political inheritance in recent British history. When she claims that the current political climate exceeds even the Brexit period in its divisiveness, she is making a specific, testable statement — not rhetorical flourish. The Brexit referendum itself stands as the benchmark of recent UK polarisation: a campaign centred on identity, sovereignty, and economic direction that produced a narrow 52-48 split and years of parliamentary gridlock.

There is documented evidence supporting her claim. Parliamentary authorities, police services, and multiple inquiries have tracked rising threats against elected representatives over the past decade — online harassment, physical intimidation, and two fatal attacks. Sir David Amess was murdered in 2021, four years after Cox. That a sitting legislator with direct personal exposure to political violence characterises the current environment as having worsened, not stabilised, raises questions about whether the measures introduced since 2016 — enhanced security for MPs, improved online reporting tools, revised constituency surgery protocols — have actually worked.

The backdrop matters. The UK in mid-2026 operates under a Labour government managing a substantial legislative agenda. Leadbeater herself steered the Terminally Ill Adults (End of Life) Bill through the Commons earlier this year. Yet the broader political landscape remains fractured along lines that predate and now extend beyond Brexit: immigration, cost of living, constitutional questions, and post-pandemic economic strain. Polarisation here is not merely atmosphere; it is measurable in electoral geography, media consumption patterns, and how MPs actually behave in parliament.

What becomes clear is an accountability question. If the protective mechanisms put in place after Cox's murder have not arrested the deterioration of conditions for elected representatives, then what would actually work? The answer is not obvious. Leadbeater has named the problem on the anniversary of her sister's death; she has not offered a solution. That gap between diagnosis and remedy is now where attention must turn.