His hands are shaking so violently when he rings Jennifer that he can barely manage to press the "send" button on his mobile. He makes a stupid excuse – he's suddenly got very ill, and he's so sorry, and he'll try to make it up to her – and he realizes when he ends the call that he'll probably never speak to her again, save perhaps a coffee purchase or two. Even then, he'll avoid that coffee cart.

Sitting alone in his bedroom, he surveys the space – cleaner than normal, just in case Jennifer had wanted to – Jesus, he's a tosser. When did this happen? He was never this guy. He feels genuinely like he might be sick, so he lets his body fold in half, his head dropping down close to his knees, and tries to take deep breaths. After a while, he realises that it's probably very bad manners on his part to leave Sybil sitting out in the living room alone, even if she knows that he's had something of a shock. He scrubs at his face with his hands and is up and out of the room before he can change his mind.

"I'm on the Pill," she says without preamble when she hears his footsteps on the living room floor. She's sitting on the sofa, her back to him. "I promise. I want you to know that. I don't know why it didn't work."

He thinks about that second time they were together that night, his utter selfishness in deciding to build some sort of fantasy moment with her rather than being intelligent and realistic about the risks and the dangers of unprotected sex. "It's as much my fault if not more," he manages to croak out as he pulls out one of the rickety dining chairs and sinks into it. "I can't believe I even asked you if it was okay without a condom, let alone actually going ahead with it. I promise I'm not really that stupid. And I'm clean. You don't have to worry about any of that."

"Good. So am I. That's good." She presses her lips together into a thin little line. "It was a strange night."

There's a long silence before she quietly ventures, "Do you know who I am, Tom?"

He hesitates. "I didn't know that night."

She nods. "I didn't think you did. I'm so sorry I didn't say, it's just that people tend to treat me so differently when they know…"

"I do know now. A friend who was also at Keeler's that night sort of told me the next day." He shakes his head. "I was … surprised."

She laughs sharply. "I'll bet you were." She sighs. "This is just … Christ, I have no idea what I'm supposed to say about any of this."

"Neither do I." His shoulders slump. "Do you know what I do? Anything about me?" He rubs the back of his neck. "I can't remember what I might have told you."

"Uh, yes," she says. "You're – you write speeches for Corin MacLeod."

"Yes."

"That's – I know this is awkward for you." She stands suddenly and starts slowly pacing around the small space, worrying the cuffs of her jumper in her fists. "I know – anyway, I've thought a lot for the past week or so, and I'm going to keep it. And I thought you deserved to know. But if you don't want – I mean, if you're not…"

"I don't know," he blurts. "I mean, it's my responsibility, and I know that, and I'm prepared for that – well, not prepared, exactly – but I don't know…" He sucks in a deep breath. "We just barely know each other, you know? And my job is basically to try to take away your father's job. And you're an aristocrat, for God's sake, and my father was in the IRA. And now there's going to be a baby, and I'm—"

"Your father was in the IRA?" she interrupts, blanching a little.

Images filter through his mind – his father's dark hair, his bearded chin, the bright light in the flat as everything ended. "He's dead. But yes, he was."

"Did he go to prison?"

"Once. For a few years." He picks at a bit of lint on his trousers.

"Oh." She sits down heavily on the sofa again and hugs a pillow to her chest. "This is mad. This is all mad."

He starts to feel ill again. "I don't know what I'm supposed to say. I've never gotten a girl pregnant before."

"I've never been pregnant before," she retorts, pressing her face against the cushion.

There's a long silence – a very long silence. Eventually he gets up and goes into the kitchen to start putting the dinner things away. There's one Sainsbury's chicken gone to waste.

For a moment, he tries something – tries to imagine what it would be like if the two of them were really together and parents. He could imagine her as his partner in his bed, why not in his kitchen? He would be rinsing the dishes from their supper while she coaxed baby food into the uncooperative mouth of a child in a high chair. It would be his turn to take charge of the bath, and he'd wrap the clean child in warm towels and rock him, her, whatever, to sleep.

Maybe he could do it? This was awful on so many levels. But perhaps it could be alright in the end, if they just—

"Tom?"

He leans against the doorframe that separates the little galley kitchen from the living space and regards her.

"I'm going to go home now. I want to go to bed."

He nods, scuffing the toe of his shoe against the floor. "Okay."

"I feel like I've just ruined your entire life."

"Ditto," he replies with a humourless laugh.

"Listen…" she stands and reaches for her jacket, shrugging it on. "No matter what, I just thought – I went home with you because I really liked you. And you were kind and nice to me. And everything was good – I mean, it was really good. I didn't call you because men who get involved with me end up in the papers, and they resent me, and I didn't want to do that to you, because you were so … I don't know, you seemed different somehow. And now I've gone and done it anyway."

He starts to reply, but she holds up a hand. "Your life doesn't have to change. No one has to know it's yours."

"People saw us at that party. It's going to get out no matter what," he points out.

"I'll deny it."

He swallows. "If you like."

She shakes her head, frustrated tears coming to her eyes. "No, that's not what I mean – I'll do it for you. I'm not ashamed that it's yours. But if you're just going to resent this and hate me, then we should just forget I ever said anything." She picks up her bag and rummages in it furiously. "I shouldn't have said anything. Just – I'll get rid of it, how about that? I'll tell you that, and then no matter what I actually do, you can tell people that I told you that."

She's on the edge of a considerable freak out, he can feel it, so he steps closer to her and puts his hands on her upper arms. "Take a deep breath. Don't panic."

And then she's crying, and he feels like he's in the Twilight Zone. "My father's going to kill me," she rasps, hiccoughing on a sob as he wraps his arms around her and lets her cry into his chest.

When her sobs quiet, he tentatively begins, "Have you told anyone else? Do you have anyone else to talk to?"

"I haven't told anyone. I took a train to Kent to buy the test, and I took it in the loo at Tesco."

He can't stop himself from laughing a little. "Kent? Why Kent?"

"I don't know. It was the next train that left." She pulls back a little and frowns at the damp mess she's made on the front of his shirt. "Ugh. Sorry."

"Eh, it's fine. You should tell them, you know. You're an adult, it's not as if you're a teenager. They'll understand."

She snorts. "Right. Because that's what Papa wants when there's going to be an election next year. One daughter who gets in fights on Question Time, one who lives with a lesbian sculptor, and one who's unmarried and pregnant at 23 by a Labour speechwriter. Yes, that sounds like the perfect Tory PM Christmas card, doesn't it?"

He wants to ask about the lesbian sculptor bit but decides that now is not the time. "I won't pretend to understand."

She shakes her head. "Yes. Right. I know." She looks at him. "If you decided you wanted to be involved, I just think you should know. It would start with the photographers, camped outside your building every morning, waiting to follow you to work. Then there would be stories in the paper – not just about you, but about your family, your work colleagues, the places you go, the people you see. They would say that you were besotted with me, and therefore a fool, or were cruel to me, and therefore a monster. They would not stop until they were able to use you to leverage something they wanted – an election, a resignation, even just a punch line." She takes a deep breath. "I love my father dearly, but my life would be very different if he weren't who he is. You can make a choice about this. I never could."

She starts to go, and in his frantic rush to stop her, he puts a hand on her abdomen. She looks down at his fingers, spread there over where their child is growing. Their child. "I want to help. I don't know how much you want me to do. But I don't want to just forget you told me."

Her smile is a little sad. "I know. You showed me the kind of man you are that night, Tom. I'm so glad you were honest with me, even if I wasn't with you." She nods before squeezing his hand briefly.

At the door, she turns and rummages again in her bag. "Here." She scribbles on the back of a receipt. "My number. Can I have yours?"

He nods a little dumbly and recites it mechanically. She punches the digits into her phone. "Good. I will ring you this time, I promise."

"If you need to talk about this – I really think you should tell someone, but if you don't, and you want to talk…"

"Okay," she says softly, before turning and disappearing down the corridor.

Okay, he thinks. Bloody hell, he thinks. He closes the door and sits down heavily on the floor, resting his head on his knees. He spends the rest of the evening trying to imagine a small human calling him "Da" – and trying to imagine a world in which the prime minister will not have MI5 murder him quietly in his sleep.