"It's too bloody big," she says grumpily. "Sometimes I hear noises and wake up convinced that blasted city is still in here somewhere."

"Pretty much," she says. "Actually, it's not a phone box, it's just a blank grey cubicle, but the chameleon circuit got stuck and I've never been able to fix it. It's not so much inside as. . . it's dimensionally transcendental. The inside and the outside are in different dimensions."