‘California is the epicentre of US surrogacy,’ Miranda went on. ‘They’re seeing a rise in social surrogacy there – that’s if you just don’t want to be pregnant for whatever reason. Too busy running your company, or you’re a bikini model who doesn’t fancy a year or more out of the business. It’s hugely expensive though, and the price is rising, partly because there is more competition for would-be surrogates. Some of the brokers have started targeting military wives, because they’re often stuck in the middle of nowhere and struggle to get into employment.’

‘How nice,’ said Casey.

‘So it’s quite possible that our man in Bangladesh has spotted a viable market. If they can do surrogacy on the cheap in Bangladesh and get passports, while broadly maintaining appearances for the hopeful parents, then there’s the potential to make a lot of money.’

‘OK.’ Casey rubbed her forehead.

‘The other complication is that different religions take different approaches. IVF isn’t acceptable to some Catholics, partly because of the creation – and potential destruction – of embryos. The more conservative Jews don’t accept it either.’

‘Endless problems.’

‘Quite. It would most likely be regarded as unacceptable in Bangladesh, which could be why it has to happen under the radar.’

Hessa reappeared, with a tray and three cups of tea.

‘I think I found out about that British company operating in Africa,’ Hessa said. ‘The one that Bantham mentioned.’

She passed over her careful notes to Casey.

‘Tartarus Energy,’ Casey read aloud. ‘Registered in the Isle of Man, chaired by a South African oil man and owned through a Bermuda-based company. But there are a couple of Tory grandees on the board, and a serviced office with a brass nameplate on the door near St James’s Park, and so of course our MPs go into battle for it.’

She clicked on their website, a row of smiling suits under a logo of a charging bull.

Casey sighed, and put the notes to one side, swallowing a mouthful of tea. ‘Good work, Hess.’ Casey turned to her. ‘Now, can you call this number?’

It was the number that Romida had used to call her mother. Untraceable, Casey had discovered. Almost certainly a burner.

‘Are you sure?’ Hessa looked nervous.

‘You’ll be great,’ said Casey. ‘You know how to do it.’

And Hessa took a deep breath, and dialled the number.

Hello, can I speak to Anu please? In her best Bengali.

This is not his phone. A rough voice, a man’s voice.

Oh, silly me. Who is this then?

Don’t call this number again.

The line went dead. Hessa looked around at them in a silence. ‘Sorry.’

‘Why?’ Miranda was smiling at her. ‘You did brilliantly.’

Casey had stopped the recording. ‘Can you tell where he was from, that man?’