Due to the lack of survival of records, it is not certain when in the thirteenth century most of the counties and the older boroughs were enfranchised. All the historic counties, except Cheshire and Durham, are deemed to have been enfranchised in 1290 for the purposes of this list. The oldest parliamentary boroughs are deemed to have been enfranchised in 1295, when a contemporary official list is available. However, as the 1295 list does not include London it may not be complete.