Dr Warr studied Fine Art at Newcastle University (1985-1987) and History of Art at Nottingham University (1987-1989). She completed her Ph.D. on Female Patronage and Female Spirituality in Italian Art of the Thirteenth and Fourteenth Centuries in 1994 (University of Warwick). She has taught at Queen's University Belfast (1999-2003) and the University of Aberdeen (1995-1996) as well as the Open University (1995) and the American University of Rome (1998). Since 2003 she has taught at the University of Manchester.
Dr Warr has held research awards from the Leverhulme Trust (1996-1998 and 2002-2003), the British School at Rome (1991, 1997-1998, 2011), the Gladys Krieble Delmas Foundation (1993), and St. John's College, Oxford (2003). From 2007 to 2011 she was reviews editor for Art History and served on the Editorial Committee of Manchester University Press from 2012 to 2015. She is currently (2012 onwards) president of the Manchester Medieval Society.
She is the author of Dressing for Heaven: Religious Clothing in Italy, 1215-1545 (Manchester University Press, 2010) and has co-edited two books on art in Naples with Professor Janis Elliott: The Church of Santa Maria Donna Regina: Art, Iconography and Patronage in Fourteenth-Century Naples (Ashgate, 2004) and Art and Architecture in Naples, 1266-1713: New Approaches (Wiley-Blackwell, 2010). Most recently, she has been working on miraculous wounds and has co-edited, with Dr Anne Kirkham, Wounds in the Middle Ages (Ashgate, 2014). She is the author of a number of articles on miraculous wounds, including 'Pierfrancesco Fiorentino’s Altarpiece (1494) of the Virgin and Child in San Gimignano and Dominican definitions of stigmata’, in Archivio italiano per la storia della pieta 26 (2013), 125-150; ‘Visualising stigmata: stigmatic saints and crises of representation in late medieval and early modern Italy’, Studies in Church History: Saints and Sanctity (2011), 228-247; and ‘Re-reading the relationship between devotional images, visions and the body: Clare of Montefalco and Margaret of Città di Castello’, Viator 38 (2007), 217-250.