Teachers calmed children returning from a school trip to France by conducting a sing-along when a suspected stowaway began banging on the underside of their coach.
Worried staff from Hummersknott Academy near Darlington, County Durham, rang police as they headed towards London, who told them to carry on driving until officers could meet them.
Police found the man hanging on to the rear axle of the coach and he was arrested without him coming into contact with any of the 47 children, who were aged between 11 and 13.
The incident happened as the pupils returned from a successful trip to Paris last Wednesday.
They had come through the Channel Tunnel and were approaching the outskirts of London when the banging started.
Teachers kept the children calm by leading a 20-minute sing-song, including If You're Happy And You Know It and Always Look On The Bright Side Of Life.
The bus was heading for Bromley, south east London, but after the commotion set off for Lewisham police station.
The vehicle's satellite navigation system took them down narrow roads, so it was met by a group of patrol cars.
Hummersknott head Pat Howarth said: "Initially the children wouldn't have known what was going on and I think their first reaction was that they were quite scared.
"The staff intervention, starting the communal singing, got them in a calm state."