As Jane got out her pocket notebook to jot down the name and phone number, two workmen got up from their table and left. The enticing smell of roast beef, potatoes and vegetables wafted out from the open door onto the street. One of the men did a thumbs-up to Emma and said, ‘All right, luv?’, but she ignored him. Jane recalled Emma had said that she’d never been in the cafe, but it seemed as if the man had recognised her.

Jane looked at her watch. ‘It’s nearly two o’clock, so we’d better make our way to the sorting office if we want to catch Rachel when she leaves work.’

‘It’s just around the corner. I’ll nip in and tell her who you are first, if that’s OK with you?’ Emma said as they approached the building.

Jane started to make a drawing of the layout of the Bluebird cafe in her pocket notebook while she waited. A few minutes later she saw Emma come out of the sorting office with Rachel, and was instantly struck by the resemblance between them. The only difference was that Rachel’s shoulder-length hair had some grey streaks in it and she was wearing a Post Office uniform under her open black mac.

‘Rachel, this is Jane Tennison.’

‘I’m pleased to meet you. It hadn’t dawned on me you were twins,’ Jane said.

‘Born identical, but different now we’re older,’ Emma remarked.

Rachel, with her right hand closed in a thumbs-up position, brushed her thumb along her chin before holding her index fingers upright in front of her body. She moved her fingers towards each other, so they touched and then pointed them at Jane, who was unsure what she was signing, apart from ‘hello’.

‘Rachel said she’s pleased to meet you,’ Emma told her.

Jane smiled as she shook hands with Rachel, then spoke slowly, accentuating her lip movements.

‘I’m very . . . pleased . . . to meet . . . you too—’

Emma interjected. ‘It’s OK, Jane, you can speak normally – it’s actually easier for Rachel to understand what you’re saying if you do.’

‘I’m sorry, I hope you weren’t offended.’

Rachel shrugged her shoulders and did some sign language to Emma.

‘She said she can’t hear you – so no offence taken.’

Jane smiled awkwardly at the joke. ‘Are you happy to talk to me about the men you saw in the cafe on Monday you thought were talking about a robbery?’

She looked anxious and did some more sign language to Emma, who translated.

‘I told her you were investigating a robbery. Rachel’s very nervous and doesn’t want to talk about it near the cafe or in the police station.’

Jane looked at Rachel. ‘That’s totally understandable. We can do it at your flat if you like?’

Rachel nodded.

‘My car’s just up the road. Where do you live?’