You will be aware of the government Inquiry into security service strategy against terror which the incoming administration appointed me to chair last year. There is a missing expertise in the Inquiry which I believe you are uniquely qualified to provide. Formally speaking, this approach should be coming not from me but from the Government Legal Department which administers such matters. However, I have overwhelming and powerful reasons for initially speaking to you alone.

I would therefore be most grateful if, in the first instance, you would meet me privately. I cannot impress upon you too strongly that it is vital for my sake, if not yours, that this meeting is confidential and unobserved. I leave it to you to arrange a time and place that would suit these criteria. I can travel anonymously by bicycle. Anywhere within reach of Vauxhall Cross would be suitable. The meeting would be purely exploratory and you would be making no commitment by agreeing to it. However, I do not exaggerate when I say that truly vital matters of state and possible wrong-doing are at stake.

I would ask you to deliver your reply hand-written to the address above. I hope very much to hear from you with your arrangement.

Yours most sincerely

Francis Morahan

Sara stood up with a jerk, blood rushing from her head. Both the author’s identity and the fretfulness of the letter were a shock. She took a few deep breaths. Her thumping heart began to slow and the colour returned to her face. She wondered at how such perfect, concise sentences could emerge from such an apparently shaky hand. She didn’t dare to step out of the cubicle until she’d calmed down. It was the most disconcerting letter she had ever received, prompting a scattergun of questions and images. Chambers was not the place to confront them.

She walked back to her room; for once she was relieved to find Sheila gone. She stuffed the next day’s briefs and a sheaf of articles on cybercrime into her bag, grabbed her coat and headed for the exit. Ludo’s door was open – deliberately, she suspected.

‘Go on then,’ he grinned. ‘Something interesting?’

‘Really, Ludo, is not a lady’s privacy to be protected?’

He wasn’t buying it. ‘If it’s an offer, tell them to sod off. It’s my firm intention, Sara Shah, to clamp you in chains to 14 Knightly Court until my retiring day.’

She wandered over, gave him a pat on the shoulder, and headed out into the street, making for the Embankment. The sun was dipping beyond Big Ben and the skyscrapers of the new Vauxhall megacity. She crossed Waterloo Bridge, losing herself among the swathes of homeward-bound commuters. She found herself staring at the London Eye. The memory of that day – when it was still the new, exciting addition to the capital’s skyline called the Millennium Wheel – struck her like a smack of iced water.