On her astonishing third album the 24-year old singer-songwriter deftly bookends a set of vulnerable love songs with two protest anthems.
The Bragg comparisons are inevitable, although Petrie's crystal clear and often soaring vocals mean her songs are far easier on the ear.
And has Bragg ever written anything as sadly beautiful as Baby Blue with its heartbreaking lament "Oh my lover is in the arms of another tonight?"
An angry, caustic indictment of the coalition government's cuts agenda, closing track Farewell to Welfare name checks Section 28, Theresa May, Harvey Milk and the "millionaire in Downing Street."
A protest star is born.
Ian Sinclair