She crosses Hungerford Bridge and turns right along the river, the lightest of rain refreshing her. She looks around. Far to the west, beyond the pale grey hovering over the Thames, the sky is brighter. The day will clear. It will be the same as any other.

A bus on the opposite side of the Embankment, its passengers’ faces like polka dots, heads towards the city.

‘… buses or tubes…’

The buses and tubes are running normally. There’s no sign of any strike action – or boycott. No demonstrators or posters.

The nag becomes a throb.

At Chambers she is greeted with smiles. It seems that, even if everyone else here is white and English, they like her and want her for the youth and difference she’ll bring.

The clerk inspects her. ‘Are you OK?’ She detects his concern.

‘Yeah, fine,’ she smiles. What’s he noticed? ‘Just murder on the tube.’

What made her say that?

She wants to ask if anyone else got the same weird text that she did. But if none of them did, she can imagine them staring at her – who’s the weirdo here?

She sits at her desk, fires up her computer and begins to study her case files. She can’t concentrate, fingers sweating, slipping and sliding over keys. She feels the other three in her office watching her and looks up. Their heads are glued to screens. Instead, the face of that guy with the rucksack flashes before her.

It’s no good. It won’t go away. She looks at her watch – 9.21 am. Still most of the day to come. Surely loads of others must have got the text – the authorities probably know about it already. Even so, she should warn them, however nonsensical it might seem. But how? She’s a young Muslim woman – might that not raise questions? Cast suspicion on her? Might they want to interview her father? Even her new colleagues in Chambers?

Best if there was some kind of anonymous helpline. She’ll check for that on her computer. Head-down, concentrating on her search, she hears a distant sound. Sirens.

She hits a number for the Met’s confidential line and dials it.

She hears more sirens. She looks up – her office colleagues are hurrying towards a window. She’s seized by dread, stops dialling, puts the phone back. Is something happening?

She clicks on the BBC website. The 7th of July 2005. Nothing. The news is still all about the Olympics. The sirens are just an accident, a fire, usual thing, a day like any other, she repeats to herself.

She dials again. A recorded message tells her to hold on, someone will be with her very soon. ‘Please don’t hang up.’

Suddenly the BBC website flashes up ‘breaking news’.

First reports of a massive disturbance on London’s underground system

Slowly and silently, she puts down the phone and stares blankly ahead. A terror dawns.