Thanks for the replies. Iv'e just checked on https://tfl.gov.uk as you recommended, and it shows that my motorhome is compliant in London. Just to muddy the waters I also checked cwww.gov.uk/clean-air-zones as mentioned by derek500. This site shows I am compliant in Bath, Bradford and Portsmouth, but not in Birmingham, Bristol, Sheffield or Tyneside. Since my van is Euro 5, I wondered what TFL and other cities actual criterion are for deciding what is and what isn't compliant. This was brought to mind recently in an article I read on line by someone with exactly the same situation and I am curious to know why.