Last week I had a lot of trouble getting to and from work as an unexploded world war two bomb was discovered in Bromley-by-bow. All east-bound trains and tubes were suspended for three days past the site and the advice given to commuters was "avoid traveling if possible". Four extra connections, additional walks, and several hours later, I was able to make my destination.
According to one article, approximately 84 unexploded bombs fell on Britain each day between September 1940 and July 1941. I guess I can expect a few more delays.
