Also worth noting that unexploded bombs from the Second World War still turn up in London every now and again, e.g. 21 May in Wembley [0], 14 May in Bromley [1], 23 March in Bermondsey [2], 20 February in New Malden [3].
[0] http://www.theguardian.com/uk-news/2015/may/22/bomb-found-20...
[1] http://www.standard.co.uk/news/london/pensioner-finds-unexpl...
[2] http://www.standard.co.uk/news/london/police-called-in-after...
[3] http://www.standard.co.uk/news/london/police-investigate-une...