Harvey Milk, “the opera” – music by Stewart Wallace, libretto by Michael Korie – is the latest in a series of home-grown commissions that have put the enterprising Houston Grand Opera Company on the international map. And in Houston, Texas? Who’d have thought the Milk train would ever stop there But ithas. But to be the subject of an opera, his very own diva? Now there’s an irony. The JLE is not only an engineer’s dream, it is much needed: my cab back to Bond Street took an hour.. An opera queen in life, the former mayor of San Francisco Harvey Milk has become a diva in death. Edward Seckerson watches an all-gay all-American hero discover his voice in redneck country Harvey Milk loved the opera He lived and breathed the opera.

The night before his assassination – 27 November 1978 – he was at the opera: Puccini’s Tosca. But it’s a dangerous job: eight workers died on the British end of the Chunnel.Six hours later, I re-emerge into the winter sunshine. Hailing a cab, I watch as the cranes swing another load of concrete segments on to a lorry. Critics say the money should be spent on existing Tubes, buses, or bicycle lanes They are wrong. One reason these jobs are so tribally cherished is that they can bring in £40,000 a year.

Others aredealing with the spoil, laying new tracks or fixing the lights. And others are keeping Tracy happy with her favourite tipple: 10,000 volts of electricity.Chatting to the miners, it is clear that the profession of tunneller is a clannish one. A lot have worked together on past projects, and many hail from the same parts of Ireland, Scotland or Cornwall. Tunnelling con-tinues through the night Monday to Friday; weekends are reserved for maintenance David Shepherd explains how every man has a different task Some are bolting into place the curved concrete panels. Every half hour she halts, and the men start fitting the concrete segments behind – constructing the tunnel lining There are 10 men on this team Each team works an eight-hour shift, five shifts a week. Seeing as it feels about 3 million degrees up here in Tracy’s tiny brain, we must be drilling through some pretty rough stuff, right? Jim looks at me pityingly: “Wrong.”The day progresses Tracy edges forward, chewing her way through clay and shale. As Jim explains, the faster we go or the trickier the going, the hotter it gets.

Tracy is a big girl: 100ft-long hardened steel cylinder, packed with electronics, guided by laser beams, equipped with ground probes and gyroscopes, and tooled with a dozen big tungsten carbide drillheads.Up in the cab, I stand with Tracy’s driver, Jim Gilbain, and start my day’s work. The miners of the JLE have nicknamed their huge Canadian-designed tunnelling machines after certain types of girl. This one is called Tracy because she’s heading for Essex, she’s usually boring, and with a bit of luck she’ll go all the way. Much of the land in the north Greenwich peninsula has been contam-inated by the chemical plants and gasworks previously sited there – even this far underground the rich clay is shot through with cyanide, arsenic, mercury and sulphur.As we round a corner I hear shouts The concrete cavity shudders I smell oil and sweat, and suddenly there she is: Tracy. Once past the whirring water pump we see journey’s end.Huge train-loads of slurry and muck are being expressed past us, back to the surface The soil seems to glisten.