The bus moved off again. I felt the lurch as it turned sharp left into the depot, the rackety sound of its engine bouncing off the cavern walls. In quick succession after that came a squeak of brakes, a slam of the cab door as the driver hopped down, a shout of welcome, footsteps - and, finally, an eerie quiet.

 "Keep down, there'll be more to come yet," Motto whispered, reminding me of what he'd gleaned from his timetable studying.

 For the next twenty minutes we stayed tucked where we were, hardly breathing, as other buses came in from their various routes, their engines revving as they were reversed into position, then turned off for the night.

Above us, through the rear window, I could see the dome-shaped lights dangling from the depot ceiling.

 Motto checked his watch. "Not long now," he said.

 Finally, I heard the clanking of the metal shutter doors being rolled down. Footsteps echoed, then came a lower rumbling as the concertina panel between the depot building and the overflow area was wheeled shut. The dome lights flicked off. A door clicked shut.

 In the silence Motto gave a hiss of triumph. "Pete! We are in, kid!"