thanks so much for your replies!
so its' eurostar; I will look at the website.
Now I'm thinking if I should stay one night; if the train arrives around midnight, it will be a bit late for me on my own in London especially when I don't know it well. But then again it is safe in London, right? If I find a B&B at Paddington I can still get there after midnight from St Pancras, right?
thanks again
love satchi