Plastic banknotes have been in circulation worldwide for decades and Britain is way behind the curve on this. 
Have other countries put War criminals on theirs, or are we the first?
You referring to the bombing of Dresden Harris?
Yup.
Bomber Harris never was and never will be a criminal, he was side stepped because of political pressure from the spanks, which Churchill gave into, his area bombing was sanctioned, by Churchill,and the Air ministry, Dresden was a much rail terminus for troops heading to the eastern front, and the west, Dresden burned,because of the large amount of wooden,and timber framed houses.
He took the war to the Germans front door,
He died a troubled man because "his boys" were not allowed a war medal, he fought till he died,
Bomber command now have a beautiful memorial, in green park,.a testament to a 70 year fight to be recognised, for the sacrifice 55,000 people made, and have now been remembered as they should have been 70 years ago.
Long live there memory, along with bomber Harris.