IT HAD ALL STARTED IN A HOTEL SUITE IN PARK LANE. We were there with Hollywood director James Cameron to discuss the funding of saturation dives on Titanic's sister-ship, Britannic, but we never really thought it would happen.
     Then the emailed invitation arrived: Would you like to dive the Titanic
     It was mid-June, and only a few days later Leigh Bishop, Carl Spencer and I were flying to St Johns, Newfoundland. St Johns is one of those places where you expect to find polar bears rummaging through the dustbins.
     I had seen the research ship Akademik Mstislav Keldysh from the air - a big white whale, almost the size of the iceberg just outside the harbour entrance (icebergs in June Could this be an omen). After a day ashore, the ship was ready to depart.
     The Keldysh, capable of visiting 80% of the worlds oceans, was used as a marine research vessel by the Russians before the Berlin Wall fell and, although no longer funded by the Russian government, still fulfils that role. However, she also relies on private charters from scientists and tourists to visit sites such as the Titanic and the mid-ocean geothermal vents.
     She was also used by James Cameron to gather much of the footage for Titanic, and the crew themselves acted in the movie. As Cameron says: These guys are the real deal.
     So here we were, a diving instructor, a heating engineer and a fire-fighter, on route to the worlds most famous shipwreck aboard one of the industrys most famous ships. Divers regular deep-wreck man Leigh Bishop was along to work the camera systems for us, while Carl and I could look forward to a seat in one of the MIR submersibles, two of only four deep-diving submarines in the world. The Kelydsh is the only operation capable of launching two subs together.
     As if we didnt feel out of place enough, the guest list of scientists read like a Nobel Prize dinner entrance card.
     We werent on some jolly, however. This was a joint scientific expedition with the US National Oceanic & Atmospheric Administration (NOAA), and we had been assigned several experiments to complete, as well as wanting to identify certain sections of the ship to help with our own penetrations of Britannic.

The fantastic Russian crew seemed to appear from all over the place; you never saw the same face twice. Some 120 of them were secreted about the ship, all very cheerful and helpful but mostly non-English speaking, so briefings had the same surreal air as orders for lunch (Leigh would point at what he wanted on the menu, only to be served something completely different).
     Carl and I were to accompany a Russian-speaking pilot, and Carl would be frantically copying down phrases to practise on the scheduled 12-hour dive. He seemed keen to know the Russian for: Where is the water coming from
     Two days later, lying in bed, woken by the incomprehensible Russian roll call, I was aware that the ship had stopped at the site. The immediate sense of eeriness became more marked as I noticed that we were on a flat-calm sea shrouded by fog, a poignant reminder of the 1500 souls who lost their lives on that calm April night.
     Today was submersible briefing day, when we would meet our pilot and get our first look into the MIRs. These submersibles are a triumph of technology, able to reach depths in excess of 6500m (the Titanic is at a comforting 3750m, or 2.5 miles!).
     The MIR is a pressure sphere with a theoretical crush depth of 12,000m. It is about 2.5m in diameter and carries a crew of three. If you are claustrophobic, dont volunteer. The crew sphere is a mass of electrical fittings and camera gear and reminiscent of an Apollo space capsule. It felt as if there might just about be enough room for our sandwiches and us.
     In theory three men can survive for 100 hours on the life support, a CO2 absorbent pack and an oxygen injection unit. We planned to spend about seven hours on the bottom with a further five spent ascending and descending.
     As the day wore on, we all began to realise just how privileged we were to be part of this expedition.

Before diving, fluid and food intake levels are carefully monitored, as there are limited toilet facilities in the MIRs. Carl and I were to be in MIR 2. As we watched MIR 1 being launched, I found the ships hero, the O-Ring Guy. A Russian straight out of a Marx Brothers movie, he was carefully preparing the main hatch O-ring. If that failed, it would hurt.
     In reality the O-ring is designed to work only to a limited depth, and the hatch design relies on a precision face-face metal seal, but it was still nice to see him taking so much care.
     Now it was our turn, with big smiles and handshakes all round as we went through the final safety briefs.
     Eugeny Genya Chernyaev is one of the most experienced submersible pilots in the world. He has done more than 200 dives on Titanic alone.
     Inside the tiny sphere, Genya closed the hatch. Not that we wanted to, but neither of us knew the Russian for Ive changed my mind anyway.
     At 10.13am on 29 June, one of the most memorable dives of our lives began. As the sub hit the water, I could visualise the cowboy outside jumping onto the sub to release the winch cable. A nice job in calm seas but, when its rough, these fearless Russians need all the skill of a rodeo rider, and are often completely submerged while trying to connect and disconnect the MIR.
     This release ritual by the cowboys is dramatically filmed in Camerons new 3D Titanic movie Ghosts of the Abyss.

At 100m the light went out. We were falling at 30m/minute. In four minutes I had passed the deepest depth I have dived in the sea.
     10.52 and 1000m down, the water temperature had dropped to 4.2C.
     Looking out of the 20cm-thick acrylic window, I could see phosphorescent plankton shooting by like tiny rockets.
     At 2000m the temperature was 3.1C and the outside pressure 200 bar. Radio communication to the surface sounded just like an Apollo mission, with multiple acoustic echoes. At 12.25 the echo-sounder showed 100m to go as we started to correct our descent.
     Condensation dripped from the inside of the sub and Im sure Carl and I both sneaked secret glances at the hatch.
     Genya seemed unconcerned. 12.29, and a flat silty bottom came into view. Pure white brittlestars littered the seabed. MIR 1 was also down and making her way to the Titanic - the mid-ocean currents had pushed us 1km from the wreck.
     Genya explained calmly that the navigation system had crashed. We were temporarily blind, 3780m down. This was beginning to feel like Hollywood! Finally the transponders came on line and we slowly made our way to the wreck. Carl and I were each glued to a view-port.
     Titanics bow hove into view, MIR 1 shrouding the forecastle in light.
     I have dived hundreds of wrecks, but watching the MIR ballet made this even more special. Both subs glided within a metre of each other as we went about our separate missions.

Titanic is broken in two just aft of number 3 funnel, right between the boilers and the engines. The stern is 600m away. The bridge structure is gone and the telemotor stands alone, almost as a memorial.
     Titanic is alive and being consumed. At this depth, colonies of microbes, which in shallower water have too much competition, are dominant. Titanic is covered in rusty icicles or rusticles which, initially thought to be massive chemical decay, have proved to be the microbes that are slowly eating the ship. These colonies merit a complete scientific study in themselves, and attract researchers to the site. The microbes have anti-bacterial properties, environmental applications (such as clearing up oil slicks) and can even produce usable energy.
     After several hours cruising the bow, we glided to the stern. The debris field was littered with reminders of the human interaction with the ship - shoes, plates, all perfectly preserved. The stern was smashed, debris everywhere, with the main engines, towering four storeys high, the only recognisable feature.

As the MIR moved between the engines, we attempted to locate a watertight door. Never having seen one, we wanted to identify it visually before attempting swimming penetrations to locate them on Britannic. Moving between the leviathan engines was like passing through a portal guarded by two massive sphinxes. MIR 2 started to collide with wreckage, and we had to abort our penetration or risk becoming another artefact.
     At 19.14 it was time to leave. I realised that I couldnt feel my legs. Carl looked as if he could eat even a McDonalds, his repeated requests for food having fallen on deaf ears. Finally Genya succumbed and produced a picnic. It was the deepest dinner we had ever eaten.
     MIR 1 had left two hours ago and we were alone. Genya turned the lights off as we started our silent return to the daylight. We must have shot a thousand photos; if one came out we would be happy. Two and a half hours later we broke surface in the dark.
     The duty cowboy locked on and we swayed around in the increasing swell. Secured back to the deck, we powered down and the hatch opened.
     What do you say when you have just dived the Titanic, how do you greet the world again Its almost like going on stage. Amidst much cheering and clapping we emerged. Mission complete.
     Truly a day to remember.

Titanics bridge telemotor is all that remains of the bridge. Its surrounded by memorial plaques to those whose lives were lost.
As the crane lifts the submersible, the Russian crew help to prevent it swinging out of control
The remains of Captain Smiths bathroom, today with rusticle growths hanging from the ceiling.
MIR 2 moves close to a first-class stateroom on the starboard side of the boat deck