for ADSL it depends on how far you are from the exchange which is around the end of court lane and lordship lane. for FTTC it is how far you are from the cabinet (the green box in the street) However each provider will have their own equipment configured in their own way at either end of that copper wire (exchange and your house i.e the modem / router) and transport the data traffic through their own networks once they have collected it from the exchange. Offcom release a report each year comparing providers here: https://www.ofcom.org.uk/__data/assets/pdf_file/0015/100761/UK-home-broadband-performance,-November-2016-Technical-report.pdf