Your manager didn't have the right to compel you to attempt the journey. (That's confirmed at the foot of this page:
http://www.bbc.co.uk/news/business-11886185 ).
However he doesn't seem to have done that anyway; he simply encouraged you to get back in as soon as possible (while still leaving it to you to decide whether it was safe to do so).
If you're thinking of suing your employer, I'd forget it. Firstly, I think that you'd lose. Secondly, employers don't take kindly to being sued by their employees; it's not hard for them to manufacture a reason for dismissing someone regarded as a 'troublemaker'!