“Good morning, Mr. Whittington,” she said politely. “At least, au revoir , I should say.”

“Exactly. Au revoir! ” Whittington looked almost genial again, a reversion that aroused in Tuppence a faint misgiving. “ Au revoir , my clever and charming young lady.”

Tuppence sped lightly down the stairs. A wild elation possessed her. A neighbouring clock showed the time to be five minutes to twelve.

“Let’s give Tommy a surprise!” murmured Tuppence, and hailed a taxi.