If you handled the egg and removed it from the nest, probably the egg is no good. Swans will leave infertile or bad eggs on the nest to rot. The best thing that you can do is to throw the egg in the nearest pond. Swan eggs will rot until they explode leaving a very smelly mess around your house and the odor is so bad that it may not dissipate for a long time.

Incubation of swan eggs takes years of experience and the right incubation equipment, so it would be highly unlikely that you will be able to do anything with this egg. Even if you hatched the egg, this would be a great disservice to the cygnet as you would have to hand raise the cygnet until at least 6 months of age before releasing it. This means that since it is raised by humans, it will imprint and may not understand that it is a swan. You cannot domesticate a swan like a goose or duck. Imprinting will hamper the swan's return to the wild.

Because the swans are protected in England, you would possibly need a permit to raise and maintain the cygnet and would likely have to turn it over the proper wildlife authorities. The Regal Swan