not being there by thinking rubbish,’ warned May.
‘You don’t know where he is, but I have a good idea. Besides, I had the presence of mind to wear my waterproof long johns, which is more than you’re doing. I always said if anything happened to us we’d go down together. If we don’t get Tate tonight, we’ll have nothing. Look at the state of that woman downstairs, look at her eyes—they’ll get a doctor to say she’s unfit to stand trial. Is that what you want? For once in my life I’m not at all cold, and I’m coming with you.’
Accepting that winning an argument with Bryant was as likely as finding a tobacconist’s shop at the top of Everest, May gave in gracefully, and chased his partner up the stairs. They met Bimsley in the street.
‘What about getting Oliver Wilton to help?’ asked May as they headed toward the alley. ‘He knows how the system is routed.’
‘Only from above ground,’ said Bryant. ‘He’s a technician. It’s not the same as seeing the world from underneath the street. Besides, the unit couldn’t be responsible for his safety. We know Tate’s down there because he’s just re-routed the water flow. The system can be reconfigured by manipulating valves, but once the channels start to fill the power of the river becomes too great to reach them, and we’re having the heaviest rainfall in thirty years. But I’m betting there’s an overflow route, one that can be opened by high water pressure.’
‘What do you mean?’
‘An escape route; this level of flooding probably switches the largest channels. The bigger the conduit, the greater the volume of water passing through it, the more pressure it will exert. It’s a track-switching system that only gets fully tested to its maximum level every few decades. Tate used a junction-rod to clear a dry path for himself through the tunnels,’ Bryant explained. ‘He made the necessary changes, then waited for the water level to rise to the point when it would re-route to a high-volume shaft. I think one of its side effects was to put pressure on the basement wall of number 5. He explained the process to me; he even gave me a map, but we couldn’t follow it because of the rain. He wanted me to understand.’
‘Then why didn’t he simply tell you what was going on?’ May asked.
‘I don’t think he’s capable of explaining the full story to anyone, of why he was there and what has happened to him. How long has he been living on the street? Do you have any idea what that does to a person?’
The alley was under several inches of water at one end, but the raised area around the grating was virtually dry. The lid had been removed and cast aside. Bryant pointed to the iron rod sticking out of the turntable at the bottom of the shaft. ‘You see?’ he crowed. ‘He’s kept this path free for himself, and now he’s gone down to follow the re-routed channel. We’re going to lose him if we’re not careful.’
‘Could you explain what’s going on, sir?’ asked Bimsley, fighting to stay balanced in the shifting mud.
‘Later,’ Bryant promised. ‘Help me down.’
‘Are you sure it’s safe?’ Bimsley asked.
‘At the moment it’s still passable. The volume can rise at an incredible speed in times of heavy rainfall, but it also runs away fast. There are emergency drains which open to reduce pressure. I’m more worried about what will happen if it stops raining.’
‘Why?’
‘The levels will fall and switch from the overflow conduit back to this route. Which means these smaller corridors will become inundated once more.’
‘How long have we got?’ asked May.
‘That depends. The channel will take Tate directly to the St Pancras Basin, but if the rain eases up, the tunnels could switch back in just a few minutes.’
‘Then we should go overland.’
‘We have no way of tracking him from above, and to do so would be to miss the entire point. I think he wants us to follow him down there. We need the final piece to this.’
‘Then I’ll tell Janice and Meera to follow above ground, and keep us apprised of the weather conditions.’
‘How will we know where Tate’s gone?’ asked Bimsley, reluctantly lowering himself into the steaming drain.
Bryant smiled and held up his river map. ‘He left us a guide. Let’s get going.’
The first two tunnels were dry and easy to negotiate, but by the time they reached the third, it had been joined by another