Though she says she “mostly … just wanted it to be a folk record,” there are ripples of blues, jazz and a darker, gothic country running throughout. It’s a very different collection to 2013’s much praised American Kid, which pulled in themes of family, life, death and world politics.

“The songs were written at the time when my father was passing away,” she recalls of American Kid. “I was digging into his life and wanted to find out more about him, and he was not in a situation where he could tell me much. Some of the songs are these stories about him, and some of which are complete fiction – I made stuff up. And that coincided with the United States’ involvement in Afghanistan and Middle East, and a government that’s not for the people.”

For Servant Of Love, Griffin again finds herself delving in complex subject matter, from romance to the shooting of an innocent man by police in a US supermarket.

“Love and war, nature’s upheaval and resilience,” she says simply of key themes running through the 13-track collection.

Of its predecessor, she said “it’s a pretty twangy record,” and in comparison describes her latest as “more piano. Fewer traditionally structured songs.”

It’s another brave step forward for the former waitress. Hailing from Maine, on the North East tip of the USA, and now a resident of Austin, Texas, further south, Griffin first came to prominence in the early-90s after being spotted strumming in Boston coffee houses. She’s since picked up a shelf of accolades, including a Grammy, and had her songs covered by the likes of Bette Midler, The Dixie Chicks, Jessica Simpson, Emmylou Harris and soul-man Solomon Burke. She also teamed up with Robert Plant, both musically and romantically (though their relationship ended in 2014).

Back in the UK for selected dates, including Birmingham’s The Glee on Sunday 24th January 2016, she arrives with a full band and a set-list that spans her career, pulling from earlier work. But her attention is already shifting to her next US tour where, as the country races to find a new President, she’s using her profile to encourage voting.

“[The] American tour [is] with the League of Women Voter’s – our suffragettes – trying to raise attention for and efforts to getting, specifically, women to vote,” she says. “In the US, single women are the largest eligible voting group and their turn out is very low. What might happen if we became a highly respected voting force on all levels of the democratic process? I think it’s crucial that we do, so we are doing awareness raising about this. The tour is called Use Your Voice [and it’s also] with [musicians] Anais Mitchell and Sara Watkins.”

But the year ahead isn’t all about politics: “I hope to write and record later this year as well.”