London cops use an insecure mail-server that lets third parties intercept mail in transit

Best practice for mail-servers is to turn on TLS by default, which means that when that mail server talks to other mail servers, it encrypts the connection to thwart eavesdroppers. Though the practice (sometimes called "opportunistic encryption") started out as something only paranoid organizations partook of, it's now so widespread that Google warns you if you attempt to use Gmail to send a message to someone whose server won't accept encrypted connections. (more")