With the introduction of the (020) area code, as part of the Big Number Change, subscriber numbers were changed from 7-digits (xxx xxxx) to 8-digits (xxxx xxxx).
wɪððɪ ˌɪntɹədˈʌkʃən ʌvðə zˈiəɹoʊ twˈɛnti ˈɛɹiə kˈoʊd, æz pˈɑːɹt ʌvðə bˈɪɡ nˈʌmbɚ tʃˈeɪndʒ, səbskɹˈaɪbɚ nˈʌmbɚz wɜː tʃˈeɪndʒd fɹʌm sˈɛvəndˈɪdʒɪts ˌɛksˌɛksˈɛks ˌɛksˌɛksˌɛksˈɛks tʊ ˈeɪtdˈɪdʒɪts ˌɛksˌɛksˌɛksˈɛks ˌɛksˌɛksˌɛksˈɛks.