What gauge is the Tomy line?

Well I'm sure they are availible elsewhere but hornby is big in the UK! Especially for children, I had a 00 gauge hornby set when I was younger, I only ever had a single loop of track for it - my cousin had a lot more. 00 also seems pretty popular with serious modellers too, I think it's because of the size, you can appreciate tge detail, Graham Farish seem to be quite good at the moment too (in both 00 and N) and their 'scenecraft' range of scenery is really good, ( most of my buildings are scenecraft)