Sir Ed Davey has written to King Charles to explain why he believes he has to refuse his invite to a state banquet for Donald Trump.
The Lib Dem leader said on Wednesday he will be boycotting the dinner next month during the US president's second state visit to the UK because of the situation in Gaza.
He told Sky News on Thursday: "I've written to him [the King] personally explaining my thinking.
"And it's with deep regret that I've had to take the decision, but I feel with what is going on in Gaza, it's the best way I can get my voice heard."
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Sir Ed said the "sad truth" is Mr Trump is the "one man" who has the power to stop the "horrible famine in Gaza, could get the hostages released, could bring an end to thi