Sir Keir Starmer said he would not use the expletive language that Donald Trump has put in social media posts.
Asked about Mr Trump’s use of the language and phrases such as “praise be to Allah”, Sir Keir said: “Let me be really clear and blunt about this.
“They’re not words I would use or would ever use because I come at this with our British values and principles foremost and uppermost in my mind.”
Asked about Mr Trump’s threats against a “whole civilisation”, Sir Keir told ITV’s Talking Politics podcast: “Well, that’s why I say, I would never use those words and language like that myself – very important that I’m clear that the United Kingdom, we have our principles, we have our values, we will be guided by them.”
He added: “In the last few weeks, I’ve been saying we are not going to be dragged into this war because I say there must be a lawful basis – that matters.
“If you’re going to commit our service personnel to risk their lives, they need to know they’re doing so on a lawful basis.
“It’s not a question of remote international law – these are real people who take risks of their lives on our behalf.”