no its not enough time,first off you go to security,then if your passport has not been checked in london,meaning your coming off conecting flight,they send you back to visa desk,then you go back to security,the long lines circle,they put 1 bag on at a time from a circular coveyor belt,,its very slow they look at each bag before another one is put on,they are incompatant,then they stop every 10 minutes to put some worker on xray machine line stops for 5 minutes,40 minutes to get through line,then where is the train to get to the plane no sign post,that is if some one tells you you have to take train,its sign posted when your near train,before all that you have to get to terminal 5 all in all it took 2 hours from terminal one to plane in terminal 5 and that was with bording card already issued