Michael, What in the first picture would help you distinguish this from the Lombardy Poplar, Populus nigra 'Italica'?
'Italica' is narrower, and (in Britain and Ireland) also rarely healthy in our oceanic climate, being adapted to a more Mediterranean climate with hot dry summers. About 95-98% of the "Lombardy Poplars" you see in Britain and Ireland are really 'Plantierensis', and not 'Italica'. 'Plantierensis' is a cross between 'Italica' and NW Europe's native Populus nigra subsp. betulifolia; it gets its oceanic climate tolerance from the latter parent. Here's a group of 'Italica' (left; spot all the dead wood!) and 'Plantierensis' (right) for comparison: