As one of history's most enduring disasters, the sinking of the Titanic has inspired countless books analysing every conceivable detail.
However, the personal papers of the judge who conducted the original investigation just weeks later have always been beyond reach. Now Lord Mersey's descendants have made them available for the first time for a forthcoming major documentary.
The judge's notes reveal his thoughts as he listened to hundreds of witnesses. They show the extent to which he was disturbed by the Titanic's lack of lifeboat drills and its failure to slow down, even though she was travelling at night and had received ice warnings.
The nearby freighter, SS Californian, did not hear Titanic's distress calls because its wireless had been turned off for the night. When it was 19.5 miles north of Titanic's position, it had telegraphed warnings of an ice field, but the Titanic's wireless radio operators - much of whose work involved relaying passengers' messages - had even scolded them for interrupting them.
In the documentary, titled Titanic's Lost Evidence, the judge's great-great grandson, Ned Bigham, the Fifth Viscount Mersey, opens up a box holding the red leather-bound private journal that Lord Mersey kept with him throughout the inquiry, scribbling observations and diagrams.
In his judgment, Lord Mersey noted Titanic's excessive speed, but stated that he was "not able to blame Captain [Edward] Smith". He criticised Captain Stanley, of the Californian, believing that the vessel was near enough to have come to Titanic's assistance.
But his private notes show that he had grave concern over why the Titanic's engines had been steaming at near capacity, despite warnings of icebergs and why adequate lifeboat drills had not been carried out.
"Two vessels informed her: icebergs, growlers, floes." He sketched images, trying to picture icebergs that the Titanic would have seen before hitting a monstrous one some 18 metres high and 122 metres long.
In one passage, he underlined the words "no reduction of speed", adding: "Speed, 21 knots. And never reduced up to time of collision, notwithstanding wary that icebergs in vicinity and that she would be likely to meet them."
Craig Sopin, a Titanic expert and a Philadelphia lawyer, told The Sunday Telegraph: "[Lord Mersey's] personal thoughts were being recorded contemporaneously with the testimony. I've been practising law for over three decades. You don't get to see the notes of a judge. You only see the final opinion... That's what's important [here]."
He added: "For example, he questions why the Titanic was going so fast... why the lifeboat drill was cancelled, why only two boats were lowered half way in Southampton... Lord Mersey had a nautical background so, when he wrote down something questionable, he was doing that from experience."
Historians have questioned why Captain Smith did not slow down, wondering whether the blame lay with one of the Titanic's most influential passengers, J Bruce Ismay, chair of the White Star Line, Titanic's owner, which did not want it to be late with the press waiting on the docks.
The Titanic received ice warnings of danger, including one from the Baltic. Captain Smith showed a paper-written "Marconigram" to Ismay, who put it into his pocket. Lord Mersey realised the significance. Underlining the name "Ismay", he wrote of "the Baltic message, which Ismay held onto for a while".
The Titanic had 20 lifeboats. At full capacity, they could hold just half of the 2240 passengers. Lord Mersey's notes show his concern that the crew may not have even been trained sufficiently in using those lifeboats.
Mersey's inquiry led to shipping industry changes, including more lifeboats for passenger ships and 24-hour radio communications.