Blue tyres for single speed
This may be closed due to asking for opinion, but CST makes a tire called the Super HP in a wide variety of colors. I live in the states but am 99% sure you could find them across the waters as well. Another option from them would be the Czar:

http://www.csttires.com/int/bike/road-bike-tires/czar-c1406/

From my experience they are a decent affordable tire.