For incumbents to be accountable for issue stances, voters must sanction incumbents whose positions are "out-of-step". We test the electoral accountability of British legislators for their stance on Brexit. We find very limited issue accountability: individuals who disagreed with their representative's Brexit stance were three percentage points less likely to vote for them. Aggregate consequences of these individual effects are limited: a one standard deviation increase in the proportion of constituents agreeing with their incumbent's Brexit stance is associated with an increase of 0.56 percentage points in incumbent vote share. These effects are ~1.5 times larger when the main challenger has a different Brexit stance to the incumbent. A follow-up survey of Members of Parliament (MPs) shows that MPs' estimates of the effects of congruence are similar in magnitude. Our findings suggest that issue accountability is conditional and limited in magnitude even for highly salient issues such as Brexit.