Why should Britain reduce its carbon emissions when they’re only 1% of the global total? It’s not our problem – tell China, India and the US to sort themselves out. That’s a common enough view among those sceptical of climate policy.
There are a variety of responses to that, including historic emissions and the fact that some of our emissions are outsourced through trade. Hannah Ritchie of Our World in Data also points out that if every country with low emissions took that view, climate change could not be stopped:

Yes, the future depends on China doing the right thing. And the United States, Russia and India. It also depends on lots of smaller emitters remembering that they’re not exempt from responsibility.
There’s much more to explore here, but I’ll just point you to Ritchie’s newsletter on the subject. You can subscribe while you’re there – it’s very good.