When I walk onto the Grid at seven a.m. on Monday morning, Ruth is already in, going by the mug of tea steaming on the corner of her workstation, but she is nowhere in sight. My racing pulse settles down as I realise I am not going to have to face her first thing after all, until I glance towards Harry's office and see them, heads together over his desk, poring over what looks like thermal satellite images from this distance. Turning away, I move silently towards the tech suite to begin booting up my system. Colin isn't in yet, but I boot up his system too so he can log in as soon as he's at his desk. He sometimes arrives later than Harry likes, usually because he is checking a dead drop on the way into work. He generally cycles in in a bid to more easily traverse the ludicrously congested roads around the Embankment. In my view, it's a futile bid by seven-thirty a.m., on any weekday. Turning back to my machine, I key in the long series of passwords and security codes that enables me to have unfettered access to, well, just about anything, from the national CCTV network, to SIS satellites scanning the globe as they hurtle through space. There are several emails to attend to. The most important is from Harry, in his usual terse style, asking me to cross check current satellite intel with certain images captured some hours earlier. See Ruth, he writes, for further instructions.

Right, I tell myself, go and see Ruth, there's nothing to it, and after all, we are colleagues. My accelerated heartbeat betrays my nervousness as I glance over at her desk, but she is nowhere to be seen. Other team members are beginning to arrive for the day now, Sam looking secretive and preoccupied, her eyes flicking to Harry's office – he is now closeted with Adam, no doubt bringing him up to speed on the satellite intel – I will have to get onto that, I realise, as a nine a.m. briefing reminder flashes up in the bottom right hand corner of my primary screen. Sighing, I get up to look for Ruth. Her mug is no longer on her workstation return, so I infer she is most likely in the kitchen, across the Grid and past the access pods. As I pass the entrance to the Grid, Colin comes through the sliding glass doors, and we nod to each other. I glance shyly through the kitchen doorway, and there she is, making a cup of tea, her back to the door as she mops up a spill on the bench, shaking her head at her own clumsiness. I clear my throat, as my words seem to have dried up (…Ruth, wearing only a dressing gown, sitting across the table from me, pouring fragrant Darjeeling into her bone china cup…) and she looks around, blue eyes flaring with hope that fades away when she sees me. Damn Harry Pearce to Hell, I think savagely, and feel my chest beginning to tighten.

"Malcolm," she says, her tone cool and distant; for the first time since I have known her, I realise I have no idea what she is thinking. A born spook, indeed. "Er, Harry said you had some intel to cross check? Satellite images?" She nods and slips past me, keeping her distance as much as possible as she navigates the doorway. She leads the way, briskly, back to her desk, where she rummages in the detritus for a moment and unearths a folder with coloured images – SIS satellite thermal images, as I had thought – and hands it to me. "Harry wants up to date images and intel, on his desk, by 0830. He'll brief the team at 0900. Thank you." She speaks in her usual low voice, but with a clipped inflection I haven't heard her use before. It's unsettling, to say the least, this change in her. I hesitate by her desk for a second, trying to think of the right thing to say, desperate to put us back on a friendly footing, but she says again, "Harry wants that intel in an hour," and both her tone and words carry an implicit dismissal. I once heard a new administrative officer describe Ruth as "the boss spook's prize sheepdog, doing his bidding, keeping the rest of us in line" and now I can see how apt the description is (at the time I had been indignant on her behalf). I hasten back to my desk, glad to escape, and for the next hour I forget everything as I go to work, doing what I do best.

When I next look up, I notice that Sam is away from her desk, and that the blinds in Harry's office are closed. I think back over the last few days, recalling how instrumental Sam was in convincing Ruth to pursue contact with Fortescue, and try, unsuccessfully, to quell the small, uneasy voice which is whispering "it's all a setup"… but for whom? I have seen it too often, for heaven's sake, I have orchestrated enough of them, not to know one when I see one. The idea is so anxiety-provoking that it triggers the clawing pains I have long associated with the beginnings of an asthma attack, and I hunt round for my inhaler. On the other side of the tech suite, Colin raises an enquiring eyebrow – are you OK? – and for a second I indulge the idea of telling him about my extraordinary weekend, before I nod and say breathlessly, "Too much fresh air yesterday, I think!" Oh, nicely playedit's best to stick to the truth when telling a lie...

Colin grins, and says "You'd better stay inside the cabin, then, the next time we take the booze barge to Cambridge," before returning to his coding; he is working on upgrading our server security, in response to a threat from - well, that doesn't really matter. After a couple of puffs of my inhaler, my chest feels better, but the niggling voice of worry hasn't stopped. Something is going on, I'm sure of it, as I see Sam slide back into her seat. She tosses a too-bright smile in my general direction, before turning to chat loudly with Danny about his weekend activities. If only they knew what I'd been up to… I smile grimly to myself and walk through my work area to the tech storage cage. I've been meaning to audit certain stocks of gadgetry, and this would seem to be the perfect time to slink in there by myself for a few minutes.

As requested, I attend the nine a.m. briefing, but have little to add to Ruth's incisive analysis, so I sit at the far end of the table and watch her glowing as she sits on Harry's right hand side, the second-most powerful position in the room. Harry agrees with everything she says, then gives the field team their instructions, while I doodle convergent and divergent fractals in the margins of my notebook and ponder the fickleness and frailty of human nature.

I decide to avoid further direct contact with Ruth for now, and it seems that I have ceased to exist, in any case, as far as she is concerned. The rest of the team is too busy to notice, or so I think, until Sam appears at my workstation a couple of hours later, eager to hear how Ruth's adventure went. I have to remind myself that she knows only that Ruth set out with me to meet Fortescue. The fact that we then went so far off-piste as to be skiing on almost virgin snow (so to speak) is something that must remain only between the two of us. I smile insincerely at the younger woman, and tell her something innocuous. I must have said enough to satisfy her curiosity, though, because she goes on her way, looking inordinately pleased with herself. I still feel uneasy, but of far more concern to me is the sight of Ruth's tense back and hunched shoulders, as she sits at her desk, bent over her work. She doesn't move except to look towards Harry's office, as regularly as a mother checking on her newborn. I feel the insidious worm of jealousy winding its way through my gut as I see her glance again and again towards the Inner Sanctum. It's as if this weekend never happened at all. And perhaps that's what she wants…turning away, I force myself to focus on the data feed scrolling down my screens.

I don't have an opportunity to speak with her, alone, for most of the day, and my anxiety increases exponentially as a result. I feel as if I have done something wrong that I don't quite comprehend, but that everyone around me is condemning me for. It's as if I am back at school, unsure why I am again the focus of unwelcome attention from the other boys, but prepared to do anything to avoid their scorn and derision. I am thoroughly miserable, and not even Colin's newly acquired stash of Bamboo Curtain-era Chinese bugs (from his morning spent deep cleaning the…but never mind) can distract me from my growing sense of foreboding whenever I see that small, hunched figure, studiously ignoring me. Oh, heavens, what have I done? I think, fighting off my growing sense of panic. What have I done?