Piers Morgan criticised after imitating teen climate change activist Greta Thunberg

British broadcaster Piers Morgan has been criticised after imitating teenage climate change activist Greta Thunberg.

During a segment on climate change protest group Extinction Rebellion for ITV's Good Morning Britain, Morgan mocked the Swedish 16-year-old, whose passionate UN speech made headlines last month.

In an exaggerated Swedish accent, Morgan asks, "How dare you?"

"How dare you? You've stolen my morning! You've stolen my airtime! I have no life!"

One Twitter user said, "No one should be bullied and mocked ever. Greta is voicing her beliefs based on science, and she has a right to do so."

Another added, "Wtf! Just heard and seen a grown man taking the piss out of Greta who is trying to make a difference in this world and who wants to save it. @piersmorgan, you're a d***!"