One of the most famous mail service in the world. Of course they are currently handling the mails in the United Kingdom but since the United Kingdom used to be the world's largest empire, the Royal Mail has many roots overseas. In fact, most of the world's mails are based on the Royal Mail's concept. And just like all mail services, they do letters, parcels and bulk. Pretty standard for most mail services. However for most part, there were many complains about lost mails, delayed deliveries and mails sent to the wrong addresses. Honestly, which mail service in the world don't have such complains? Even mail services in small countries face the same complains. I guess when you have to deal with millions and millions of mails everyday, you will definitely lost some. You can try the email service which have less of a chance of wrong delivery. Or just pay for registered mail if that letter is important. It is interesting to note that even with email being so popular these days, actual "snail" mail services did not drop significantly.