Jack Monroe’s membership letter after joining the Greens.

Anti-poverty campaigner and food blogger Jack Monroe has joined the Green Party, it was announced on Monday.

The writer and Labour activist of ten years (she has appeared in the party’s political broadcasts) posted a photo of her Green Party welcome letter on Instagram, saying:

“It was kind of inevitable after the ‘Labour gets tough on immigration’ speeches, and been a long time coming. Hard decision in the end, but definitely feels like the right one. Still have a lot of love for the Labour Party, but just disagree with too much of it right now.”

Monroe has become famous in recent years for writing about how to cook when living on the breadline, including for the Guardian.

The move was followed by left-wing musician Grace Petrie declaring her support for the Greens in a blog post on Tuesday, saying “the UK general election is in little under two months, and I’ll be voting Green.”

Petrie said she would now be calling for people at her gigs to do the same.

Explaining why she now supports the party, she said:

Ultimately, I have to go with my heart. I have to accept that standing on a platform, however small, and speaking and singing about politics means there will be some folks out there who listen. And for those listening to me, I can’t bring myself to sell you this Labour. I don’t believe in them. I’m not trying to sell you the Greens – but I’m saying that’s where my heart is. So go with yours.

Jack Monroe has reportedly received patronising and sexist comments from Labour supporters about her decision.

The backing from both figures is clearly a huge boost to the Greens as the party nears the May election.

Are there more high-profile defections to come?