Winston Marshall has announced he is leaving Mumford & Sons, saying his departure was a “difficult decision first brought about by an unintentional Twitter storm”.

The 33-year-old banjoist and lead guitarist caused controversy earlier this year after tweeting about US journalist Andy Ngo’s book titled Unmasked: Inside Antifa’s Radical Plan To Destroy Democracy.

In a tweet – which he later deleted – Marshall said he had read the “important” book and he praised Ngo as a “brave man”.

Announcing his departure from Mumford & Sons, whose other members include Marcus Mumford, Ben Lovett and Ted Dwane, the musician said being a part of the band has been “exhilarating”.

In a statement, he said: “From odysseys through the Scottish Islands to headlining Glastonbury, from The Betsy Trotwood to Madison Square Garden. We’ve done it all. What a blessing it was to be so close to such talent as those three lads. I will look back at it all with immense pride and love. However, after much reflection and consideration, I have decided it is time to move on.

“This is a difficult decision first brought about by an unintentional Twitter storm.”

Explaining that he tweeted about the book in March, he said: “The book documents the recent activities of the extreme Left in the US. The tweet was misconstrued by many as an endorsement of the equally abhorrent Far-Right. Nothing could be further from the truth. I condemn unequivocally all political extremism, be it of the Right or Left.”

He continued: “At the time of the incident emotions were high and despite the furore, the band invited me to continue with them. Considering the pressure, that took courage.

“I’ve spent much time since reflecting, reading and listening. I know now that, as long as I am a member of the band, speaking my mind on the evils of political extremism could bring them trouble. My loyalty and love for them cannot permit that.

“However to remain in the band and self-censor will gnaw my conscience, erode my integrity. By leaving I hope to speak freely without them suffering the consequences.” 

Marshall, the son of wealthy British investor Sir Paul Marshall, said he was looking forward to “new creative projects as well as speaking and writing on a variety of issues”.

He said he will continue to work on a project he co-founded in January this year, called Hong Kong Link Up, a non-profit organisation which “aims to link up British residents with Hong Kongers arriving in the UK”.

His statement ended saying: “The band has been the ride of a lifetime. I leave with love in my heart and I wish them nothing but the best. To the band, colleagues, partners, crew, everyone who ever came to a show and everyone that supported the band, I thank you.”