london police waste resources track people may may offend muslims actual tweet promote threats violence towards non-believers find twitter round-the-clock find tweet days ago follow brussels terror attack man tweet stop muslim woman street yesterday challenge explain brussels lambast twitter comment respond criticism today insist far right merchant .matthew doyle partner south london-based talent pr agency post tweet wednesday morning say confront muslim woman croydon yesterday ask explain brussels say nothing mealy mouth reply late arrested.a metropolitan police spokeman say 46-year-old man even arrest home croydon suspicion incite racial hatred social media take south london police station enquiries continue tweet refer yesterday bomb attack belgian capital main airport metro system leave least 34 people dead 198 injure comment go viral retweeted hundreds time eventually delete mr doyle tell telegraph idea tweet would hand grenade prove twitter 140 character limit make encounter sound vastly different think go everyone get wrong confront woman say say excuse ask think incident brussels white british wear hijab tell nothing say thank explain little boy say goodbye go separate ways wednesday afternoon say someone outrage comment turn door give load abuse try throw punch inflammatory tweet mr doyle claim intend joke people know would understand absolutely far-right merchant mouthpiece kind racism radicalism say xenophobic live london muslim neighbour get burgle one first people go around help however say believe muslims enough speak terrorism horror happen brussels could happen add naive think london terror shortlist via telegraph man arrest ask muslim woman excuse ask think terror incident brussels