She had to think hard before she remembered. ‘I had a ham sandwich in the Strand, sir. At midday.’

‘Not good enough. I’m sorry for that. You must allow me to make amends.’

She didn’t show any pleasure at his suggestion but pattered resentfully after him. He was about to rethink his offer of a supporting arm but decided against it. She wouldn’t welcome the gesture and wouldn’t quite know how to refuse it.

They marched on in silence, the traffic becoming thicker as they neared Scotland Yard. Joe stopped suddenly when he reached the head of a taxi rank where a long, low building resembling a railway carriage had been constructed. Weatherboarded and painted park-bench green, it had a small black projecting iron stovepipe giving out a blast of coal, smoke and cooking food. A notice over the door declared it to be Licensed Cabman Shelter No. 402.

He put his head round the door and shouted a question. Satisfied with the rumbling response from the interior, he opened the door wider. ‘It’s for cabbies,’ he explained. ‘A sort of revictualling station. These things are everywhere in London but people hardly notice them. They’re not supposed to let just anybody in — they’d lose their licence — but if they get to know you they’ll allow you eat here. Let’s go on board and see what we can find.’

Joe took off his top hat and ducked through the low doorway. Lily followed, stepping from the chilly street into a welcoming fug.

‘Evening, Frank,’ Joe said to the whiskered man behind the counter. ‘I’d like something for this young lady to eat. She’s ravenous. In fact we both are.’

‘Evening, Captain!’ Frank looked pleased to see Joe and if he was taken aback by his white tie and tails he showed no sign of it. ‘Hungry, are you?’

‘I’ll say. We’ve just spent several hours in the restaurant at Claridges, toying with larks’ tongues and picking at plovers’ eggs.’

Frank’s moustache bristled with distaste. ‘Ah. Well, you’ll be needing a Zeppelin in the clouds with onion gravy, then. That’ll stick your ribs together.’