Hello there!
Tornadoes do appear in the UK and at some regularity that may surprise you, we get on average around 30 reported tornadoes in a year in the UK, however there may be more that go unreported because of occurring in unpopulated areas.
It may also be a surprise to find that the UK has more Tornadoes per acre of land compared to the USA, this is also because the USA is huge in comparison.
I have dug out some websites for you to look at:
Torro is the The TORnado and storm Research Organisation and is based in the UK
A Daily Mail article on Tornadoes
Hope this helps with your answer,
Dominic