A balloon depicting US President Donald Trump as an angry baby has been flown over Parliament Square in central London - but only at a height of 30 metres due to restrictions.A man at the protest wearing a "Make America Great Again" style red cap with the words "Trump Babysitter" written on it said: "We can't let him go. There are air restrictions across London as Trump is in town. We are not allowed legally to fly him. "He is at 30 meters at the moment and it's a limit. We are bringing him down to earth and we'll be bringing him to bed with no dinner and no Twitter because he's been a very, very naughty boy."The crowdfunding campaign behind the blimp had said that it would be "flown in the skies over Parliament Square" during Trump's visit.