UK 'State/province' list contains mixture of counties and large towns

The UK 'State/province' list currently contains mixture of counties and large towns. It should contain the UK counties only. There is a separate, free-text field to capture the town/city (billing_city)

For example, all of the following are Cities and should not be included:
Birmingham
Bristol
Poole

The list of uk counties listed at http://blog.acmultimedia.co.uk/2007/09/list-of-uk-counties-in-sql-csv-format/ seems to be accurate, but also needs to include the 6 Northern Ireland counties as listed at http://en.wikipedia.org/wiki/Counties_of_Northern_Ireland