Organising an interview with Christian Lindner, Germany’s federal finance minister, is like speed-dating the Scarlet Pimpernel. Our first proposed meeting – in his hulking, Nazi-era ministry in central Berlin – evaporates with 90 minutes’ notice. A second appointment is delayed, then cancelled altogether. The final, third attempt, begins more than an hour late, with effusive apologies – “I’m ridiculously busy at the moment” – and warm words for Ireland and his fiscally “like-minded” colleagues in Dublin. On Tuesday, the 45-year-old was in Dublin to meet his Irish counterparts – Michael McGrath and Paschal Donohoe – for talks on global tax...