Distances between taxiing aircraft
 

Can any pilot types shed any light as to whether there is a minimum (enforcable?) distance to be observed between aircraft on taxiways? Just wondered, as when taxiing to departure runway at AMS recently, we were sufficiently close behind the aircraft infront that I suspect we would've ploughed straight into the back of it had it stopped suddenly for some reason...thankfully, it didnt, but it did make me wonder if there is supposed to be a certain separation on taxiways and would this be monitored by ground controllers? :)