Her portrait of the businessman and writer Conrad Black and his wife, the writer Barbara Amiel, is in the collection of the National Portrait Gallery in London. In 2001, The Economist described Birley as a "modern portrait painter, in pursuit of honesty" who depicted Black and Amiel in her portrait as a "gangster and his moll".
Her painting of Conrad Black, a businessman and writer, and Barbara Amiel, another writer, is part of the National Portrait Gallery's collection. In 2001, The Economist characterized Birley as a "modern portrait artist, aiming for honesty" who portrayed Black and Amiel in her work as a "gangster and his moll".