This dragon is a symbol to fire the heart of anyone with Welsh blood in their veins. Here he is "passant" in heraldic terms, signifying greeting and [maybe] welcome. Of course he welcomes you in. Why not? He can eat you later.
The Welsh dragon is a Celtic symbol of great age and its origins are lost in legend. It is said that Romano-Welsh soldiers used the red dragon on their flag in the Fourth Century. The dragon is also tied into the legend of King Arthur - his father was Uther Pendragon. This dragon is a symbol to unite people [except maybe at Twickenham for the rugby...]
What a contrast with the loathsome monster of general folklore. From all corners of the world, tales represent dragons as evil, heartless beasts, seeking a bed of treasure to sleep on. Here they will slumber for up to a thousand years. But let anyone invade their lair, and they will strike in terrible revenge, killing a village or so and carrying off maidens to devour at their leisure.
In comes St George, cast forever as the fearless slayer of dragons. In this picture, he is in time to save the maiden. There's a story in here.
Happy St George's Day, everyone and everywhere. Let all your dragons [bar Welsh ones] be slain.