On the phone, Roberts explained who he was and asked Horton if he might be permitted to ask a question. During the last war, Roberts asked, would you ever have crept among the ships of a convoy to fire a torpedo? ‘Of course,’ replied Horton. ‘It is the only way of pressing home an attack.’ And out of interest, Roberts continued, what is the range of a U-boat’s electric torpedo? ‘Five thousand four hundred yards,’ replied Horton without hesitation.
