It was left to Keedy to point out one possibility.

‘What if we get there too late, Harv?’ he asked.

‘Too late?’

‘Cochran and Gatliffe are soldiers. By the time we reach them, they could be fighting in the front line. What if they’re already dead?’

‘Then I’ll feel terribly cheated,’ said Marmion, bristling with anger. ‘They committed a heinous crime and must be punished for it. Getting themselves killed in action would help them to escape justice and I’d hate that to happen. I want these men, Joe,’ he emphasised. ‘I want the pair of them behind bars where the bastards belong.’

War had profound social effects in Britain. When it first broke out in August 1914, the general assumption was that it would all be over by Christmas. The carnage of Mons shattered that illusion and the prime minister was soon calling for 500,000 soldiers. Women had at first confined themselves to urging men to enlist or — in some cases — sending them white feathers if they failed to do so. As more and more men joined up and went overseas, there was a crisis in the labour market. It was met by enterprising women who took over work that had hitherto been essentially a male preserve. For many of them, it was a liberating experience, allowing them to travel to places they would not otherwise have visited and to take up occupations that gave them both an income and the satisfaction of helping in the war effort.

In the course of a day, Irene Bayard found an endless sequence of jobs on offer. The problem lay in choosing the one that most attracted her. Calm and methodical, she made no instant decisions. Going from place to place, she made a mental note of over a dozen potential jobs that covered everything from nursing to operating a lathe in a factory. It was all a far cry from being a stewardess on the Lusitania and that was its appeal.

She took the opportunity to call at the shop managed by her sister and was given a cup of tea in a small room stacked high with shoeboxes. Irene had lunch alone in a cafe. Sitting in the window, she watched a number of women going past, many of them in uniforms of one kind or another. London streets had changed visibly. With recruitment at its height, there was a comparative dearth of young men counterbalanced by an increase in the number of working women. Things were different now.

It was late afternoon when she returned to the house and she planned to put her feet up for an hour. After so much walking, she was quite fatigued. The moment she let herself in, however, she heard the tinkle of Miss James’s bell. Tapping on the lodger’s door, she opened it tentatively.

‘Good afternoon, Miss James.’

‘Good afternoon,’ said the old lady from the comfort of her armchair. ‘This is the first chance I’ve had of speaking to you, Mrs Bayard.’

‘Oh, you’ll have plenty of chance from now on,’ Irene told her. ‘I’ll be living under the same roof.’

‘So I understand, dear, and I’m very happy to hear it. Your sister gets very lonely at times. Having you here will be a tonic.’

Miss James seemed smaller and frailer than when Irene had last seen her. Her face still had a faded prettiness and her white hair was as well groomed as ever, but she’d lost weight and colour. She was not idle. As she talked, the knitting needles in her hand clicked away.

‘What are you knitting?’ asked Irene.

‘That depends on whether or not you can keep a secret.’

Irene understood. ‘Oh, it’s something for Dorothy, is it?’

‘Yes, it’s a new scarf — but please don’t tell her.’

‘I won’t breathe a word, Miss James.’ She smiled invitingly. ‘Is there anything I can get you?’

‘No, thank you, dear.’

‘I just wondered why you’d rung your bell.’

‘Well, I wanted to tell you how pleased I am to see you back,’ said Miss James, ‘but I also needed to pass on a message. While you were out, a gentleman called.’

Irene was surprised. ‘Was he looking for me?’

‘Yes. I can’t really describe him because my eyesight is all but gone. But he had a nice voice and I could tell from his manner that he was fond of you.’

‘Did he give you his name?’

‘Of course,’ said the old lady. ‘I made a point of asking. His name was Mr Gill — Mr Ernest Gill.’

Irene’s heart sank.

They were miles from their destination when they first heard the continuous thunder of artillery. As they got closer, the sound grew steadily in volume. The British Expeditionary Force was undergoing a constant bombardment and retaliating accordingly. Stopping well short of Ypres itself, they established that the regiment they sought had its headquarters in an old farmhouse. The first person they encountered was a peremptory captain who treated their request with barely concealed hostility, arguing that Scotland Yard detectives had no jurisdiction over members of the BEF and that their journey had therefore been futile. Refusing to be turned away, Marmion waved the letter from the War Office under his nose and the man eventually gave them some grudging cooperation. He introduced them to Major Nicholas Birchfield, a portly man with a neat moustache, bulging blue eyes and a peppery disposition. When he’d heard them out, Birchfield clasped his hands behind his back and spoke with clipped politeness.

‘That’s all very well, Inspector,’ he began, ‘but your arrival is deuced awkward. As I’m sure you appreciate, we need every man we have. We can’t release two of our soldiers on the basis of what may turn out to be a wholly false accusation.’

‘There’s nothing false about it, Major,’ said Marmion. ‘The young lady in question was raped. A doctor confirmed it.’

‘He may have confirmed that she had intercourse but that’s hardly proof of rape. We are all men of the world, are we not?’ he went on with a ripe chuckle. ‘This situation is as old as the hills. A young woman drinks too much then gives herself willingly to a chance acquaintance. Later, when she comes to her senses, the only way that she can account for the loss of her virginity is to cry rape. It’s happened before a hundred times.’

‘Well, it’s not the case with Miss Stein.’

‘How do you know? Have you spoken to her about it?’

‘No,’ admitted Marmion, ‘but I talked with her mother. She was able to pass on the relevant details.’

‘Oh, so this is the mother’s doing, is it?’ said Birchfield, amused. ‘That settles it in my mind. What mother believes that her darling daughter would sacrifice herself before marriage? She simply has to claim that rape took place. It’s maternal instinct.’

‘We’re not only concerned with the charge of rape,’ said Keedy, annoyed by the man’s tone. ‘Murder, arson and theft are among the related crimes. In all probability, Gatliffe and Cochran may be guilty on other counts as well.’

‘Do you have any evidence to that effect, Sergeant?’

‘We know that they were at the rear of the premises at the time, Major. That’s evidence enough to make them suspects.’

‘And who provided that evidence?’

‘The young lady,’ said Marmion. ‘Miss Ruth Stein.’

‘Doing so by proxy, I gather.’

‘She was under immense stress. You have clearly never dealt with rape victims before, Major. Sergeant Keedy and I have, and we know how hard it is to get them to come forward. In all my years in the police force,’ he went on, ‘I’ve never heard one false accusation, because women know the kind of punitive cross-examination they’ll face in court, not to mention the cruel and unfair assumptions that people like you will invariably make.’

Biting back a reply, Birchfield walked behind the table that was serving as his desk. The room he was using as his office was small and low-ceilinged. It had undulating paving slabs on the floor and peeling walls. Judging by the pungent aroma, it had once been used to store cheese and other dairy products. Weighing his words, the major returned to the attack.