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 artwork featuring Conrad Black, a businessman and writer, and Barbara Amiel, another writer, is held by the National Portrait Gallery in London. In 2001, The Economist described Birley as a "modern portrait artist, seeking truth" who depicted Black and Amiel in her work as a "gangster and his moll".