Before I’d finished he tried to make himself heard, but I was determined to fend that off. I ended the call and brought up the last number so that it could be blocked, and then I stared at the screen. According to the list, the most recent call was from my mother’s number.

Were scammers able to conceal not just their number but any evidence they’d even called? I laid the mobile on the desk and was turning to my notes on the computer when the phone rang again. I didn’t bother looking until it announced my mother, and then I dabbed it with my thumb to take the call. “Where are you?” I said as gently as I could.

“Mr Semple, could you just listen to me for a moment?”

I nearly did, having been silenced by outrage. So they’d hacked into my mother’s phone somehow or at any rate stolen or copied her number. “You’re the supervisor, are you?” I said with another version of gentleness. “You think you can convince me when your man didn’t get to me.”

“Mr Semple, we just need your address so we—”

“You’re admitting you haven’t got it now, are you? So much for confirmation. I hope you don’t think I’ll be more receptive to a lady. Believe me, I wouldn’t call you one.”

“Mr Semple—”

“Go on, try and persuade me this is all legitimate. Your helper or whatever he is said you have my bank details. Let’s hear them.”

I heard muffled offstage noises again – voices and traffic, hardly the sounds of an office. In a few seconds the woman came back. “These are the last four digits of your account,” she said, “and I’ll give you the sort code as well.”

The figures were correct, which enraged me more than ever. I knew my mother kept the details in her contacts list in case she needed to make a bank transfer. I’d always found it more careless than professional, though I’d never seriously thought it could put my finances at risk, but just now I hadn’t time to blame my mother. “Do tell me how you know all that,” I said with so much restraint my head began to throb.

“It’s stored on the phone, Mr Semple, and—”

“My God, you’re admitting it. Since you’re so happy to be blatant, why don’t you tell it to the police.”

“We are the police, Mr Semple. Now if I could—”

“I haven’t heard that one before. You people never give up, do you?” With mounting rage I said “My mother authorised you to use her phone, did she? She’ll be here very shortly and you can tell her that yourself.”

“Sir, she won’t be.”