BBC News - Llandrindod Wells worst for UK drink and drug-driving rates 27 November 2014 Last updated at 13:59 Four postcode areas of Wales are among the 20 worst across the UK for drink and drug-driving, a new study has shown. Llandrindod Wells in Powys has the highest proportion of motorists with these offences with 1.98 per 1,000. Swansea is fourth with 1.76 convictions per 1,000, Cardiff is sixth with 1.71 and Newport is 12th with 1.62. The information came from analysing 11 million car insurance quotes by postcode over the past 12 months. The drink and drug-driving rate for motorists in the LD postcode is more than double that of some Greater London areas, according to the study compiled by an insurance comparison website MoneySuperMarket. The LD postcode includes Llandrindod Wells, Builth Wells, Brecon and Rhayader.