Talk to a travel agent about the various ways of getting to Newcastle. It may be possible to fly to Newcastle directly or via London, Amsterdam, Brussels or Paris. If you have to change at London, try to plan your journey as it can be slow and time consuming.
If you need to change trains at London, all trains onward to Newcastle leave from King's Cross station. This is next door to the Eurostar terminal at St. Pancras.
Connecting flights to Newcastle fly from Heathrow and Gatwick and Stansted airports.
You can join a coach/bus for Newcastle at Gatwick and Heathrow airports and from Victoria Coach Station.