Later, he thought. The top end of Lamb’s Conduit Street, after the pubs and shops, was deserted. Everyone had gone to work. This was good. The only vehicle around was a large black van with opaque windows on a meter at the park end of the street. Children leapt and danced in the little playground on the other side of the road. He glanced at the van and shook his head. London mothers. They wouldn’t let their precious little princes walk half a mile any more.

She typed what she’d discovered into an email for Middleton and made sure to mark it for encryption, adding the digital signature he’d convinced her to use always on the net. No one could read what she’d written once it traveled beyond her computer and Middleton could be assured the message really came from her, not some imposter who knew how to spoof an email address.

“Fact one,” she wrote, and she shivered as she was unable to force the true import of her words from her mind. “The picture of the dead man, Kavi Balan. What you didn’t notice was the very peculiar green brown tint to his eyes. That may be normal. But it may be a symptom of copper poisoning, due to very heavy exposure to the metal. Look up Kayser-Fleischer ring for more information. The discoloration is caused by copper deposits in the eye.”

She looked at her notes then checked her watch. Six minutes to the end of the Bach. Then she really would practice.

“Fact two. India is the world’s largest producer of heavy water. This is a very resource-intensive exercise. Depending on the process it can take up to 340,000 tons of ordinary water, H2O, to make one ton of heavy water, D2O (that’s deuterium, Harold—look it up). Maybe this is why your people are looking for new sources.”

The tea was getting tepid.

“Remember what I told you about Chernobyl and heavy water? You don’t always need it. But if you want to produce weapon-grade plutonium it’s a wonderful way of bypassing the uranium enrichment process, which involves a lot of technological infrastructure that’s impossible to hide. Not that heavy water is easy to manufacture but the process is a little like distilling cognac from wine. The difference is the conventional process uses a phosphor-bronze system to handle the distillation process whereas liquor is traditionally made using a copper still.”

She looked at the words on the page and felt proud of herself. Or, more accurately, of Bicchu, which had thrown up the answers so quickly she could scarcely believe the ease with which they had been assembled.