An accent is an individual mode of pronunciation often associated with a particular locale. A dialect is a form of speech peculiar to a district, usually employing colloquial vocabulary specific to that geographical area. In fact, George Bernard Shaw once observed that, England and America are two countries separated by a common language.
For such a small geographical area, the United Kingdom has hundreds of dialects, many existing almost side by side but sounding like different languages. I come from Yorkshire, a county once divided into three Ridings; East, West and North (Riding is an old term meaning a third – the South Riding that Winifred Holtby wrote about was fictitious), where the local dialect can be very thick. I’ve lived elsewhere in the country, and in the US, and the rough edges have been smoothed, but whenever I return to Yorkshire, I fall back into the accent and dialect without a second thought.