A sudden uptick in the South East's temperature and the coincidental close of Oxford International Women's Festival make tonight a great opportunity to experience Laura Marling's work. New record Semper Femina shows that an album can indeed pass fiction's Bechdel test, as maleness is absent from its lyrics, and its composer has the power to make such a statement both strong and unforced. Spring erupts from the stage in bouquets, among which support act Ethan Johns and band let loose their rustic songs. Best known as a producer to such luminaries as Marling, a former Beatle and Ray Lamontagne, Johns makes Americana-soaked work in thrall to the Youngs and Dylans of yore. His latest record's title track 'Silver Liner' hits home best, with its patient rhythm and lead vocal reminiscent of Robert Plant's mystic post-Zeppelin guises. The band catch most fire, though, when violinist Georgina Leach lets loose, and dialogues with the drummer's excitable snare work. Look out for Leach's work with the Moulettes and Seasick Steve.

Marling appears to significant applause, with an opening third very heavy on new material - we're treated to five songs from Semper Femina, a lesser album than which couldn't support such focus. The oft-Anglicised Joni tone of her voice is now joined by work as foundational and complexly feminist as a less temperate Hissing of Summer Lawns. Songs have a Nick-Drakeian harmonic complexity (and echoes him in the bridge of 'The Valley' with its laconic vocal lines and 'One of These Things First'-esque ticking drums, but uses feminine rhymes a little more than he did), and there is a new jazziness to the bass licks of 'Soothing', the blurred Wurlitzers of 'Wild Fire'.

But the longest and loudest applause of the night is reserved for something more unadorned. On record, the ravishing, yet simply demo-like paean to a muse 'Nouel' is adventurous, a gentle clawhammer picking pattern undergirding this account of courting and depending on inspiration. The album's title crops up here - it's a repurposed Virgil quotation, the whole of which means "woman is a various and changeable thing", but curtailed, transforms into "always a woman". "Fickle and changeable: 'Semper femina...'" describes the gloriously unpredictable Muse and the comparative frailty of the writer that here depends on Her. It's enough of an axiom that Marling has it tattooed on her body, and I'd venture to say that it's been enfleshed into her finest song. The vocal approach and style of writing are once again Mitchellesque - maybe Marling's best filtering yet of that particular inspiration.

To take us out of this central solo section (gradually), the band returns and Marling dons a twelve-string to render 'Sophia', sounding sweeter than the recording due to her bouzouki-esque tone of her axe, and suddenly at its halfway mark as timeless and propulsive as Pentangle at their rockiest. A rollicking 'Darkness Descends' (from 2010's sophomore record I Speak Because I Can, on which she had already established her mature vocal approach) is much brighter than its title may suggest, and crowd-pleasing hit 'Rambling Man' takes flight ("let it always be known that I was who I am" declares Marling, as she did those seven years ago). The evening also features the most genuinely funny, staged stage banter, in which each band member shares an arcane fact or Oxford reminiscence (underage Zodiac trips included). Lastly, 'Nothing, Not Nearly' with its borderline-glam guitar tone and the giddy internal rhyme-laden rush of a Country Music Hall of Fame songwriter, establishes Marling's multifarious approach. It's a cracking night, proof that the artist's best work may be yet to come, and my household now has a copy of Semper Femina as a result.