The sociological and national tensions between the British and Irish go back hundreds of years, but so does Britain’s obsession with Irish culture, literature, art and music. The uneasy balancing act of the UK’s Irish population is getting a close look this year at London’s National Portrait Gallery, “surveying visual representations of the artistic, literary, dramatic and political influence exercised in Victorian London by Irish incomers, determined to make their mark. Culturally fashionable Irishness was not just the result of rampant Celtic Tigerism over the past decade and a half; it has, apparently, a long-established pedigree.”