LONDON — British lawmakers endure a lot of distractions when they speak in the unruly Parliament, where their colleagues jeer, wave papers and stop them to pose questions. But one lawmaker faced a very different, harder-to-ignore sort of interruption on Monday.

Protesters stripped nearly naked in the public gallery, proclaiming that climate change, not the stalemate over Britain’s withdrawal from the European Union, was the real emergency facing the country.

“I encourage everybody to look in this direction rather than another direction,” said Peter Kyle, the Labour lawmaker who was trying in vain to hold the room’s attention as he presented a motion for a second referendum on Britain’s departure, the process known as Brexit.

[Read more about Monday’s debate.]

To his disappointment, most of the people in the elegant, wood-paneled chamber gazed upward, at the spectacle in the visitors’ gallery. There, a dozen men and women, all with messages scrawled on their bodies, stood in a row, turning their backsides to the protective glass barrier separating the public from the House of Commons, in full sight of sitting lawmakers.