DS2 is 3.5 years old and yesterday BOLTED to the street 3 times. I nearly had a heart attack. I have gone over the rules and told him either hold hands or I will strap you into the stroller (at 44 lbs he is too large for me to carry if he is fighting me while I am holding DS1's hand). So we are going to London next week. I feel like I might need a monkey harness/leash thing. We've never used one but London is busy and I think the mere threat of it might "encourage" cooperation. We will also have a stroller.

So do you have a monkey harness suggestion for a 3/4 year old at 44 lbs AND do you have another suggestion in this situation?