What is the difference between dialect and accent?

Someone may have better ideas, but I suggest that dialect refers to the whole local usage of language, local words (e.g. 'beck' for 'stream') and possibly a local way of putting words in a different order from strict standard English, or local peculiarities like the Devon 'Where are you to?' meaning 'Where are you from?'

Accent is purely concerned with the pronunciation, cadence and sound of words. It is quite possible to speak standard English in a Geordie accent, but sounds wrong to speak Geordie dialect in 'Oxford' English.