Shouldn't take more than ten minutes of your time. Be clear, concise, eloquent and grammatically correct. It may not do anything now but they will have to record all complaints and if the driver develops a history it will have to be taken into consideration if anything more serious happens.
Report the incident here: https://www.tfl.gov.uk/tfl/contact/pco/taxi.aspx
Shouldn't take more than ten minutes of your time. Be clear, concise, eloquent and grammatically correct. It may not do anything now but they will have to record all complaints and if the driver develops a history it will have to be taken into consideration if anything more serious happens.