Hexham, have you treated your dog with ant anti flea/tick products within the last 4wks? Such as Frontline, advantix? As the flea will attach but drop off by itself within 7 days. They prevent feeding so the tick will stay small and not cause any disease spread.
Otherwise as above, wait for a vet tomorrow, or pets at home if there's one nearby and grab one of the proper tick removers. They prove invaluable more times than not and cost less than £5. Easy to do yourself as well so no vet appointment needed, they can just be bought over the counter.
If your dog starts bothering at the area, you need to really get it off sooner, otherwise your dog might bite the tick off and leave the head part in the skin which can cause irritation and infection. In that case, alternative is a small wire bent to make a sharp ended V. Place the V either side of tick underneath its body next to your dogs skin.Put the sharp end of V right up to the ticks body. Move the ends of the wire together to put a slight bit of pressure around the base of tick (emphasis on slight!), then turn wire in an anti-clockwise direction (tick should start turning as well) and keep turning (takes about 4-5 turns) without ever pulling upwards and the tick should loosen by itself and come off. Make sure you throw the tick away!!
Worth considering grabbing a spot on treatment that works against ticks if your in the area for a few days as well. If you want to get one from the vets you will need an appointment. However, you can get ones just as effective from supermarket pharmacies, namely Frontline. Steer clear of Bob Martins etc that you can pick up just from the shelf on the pet aisle.