The evidence behind a decision to survey the wreck of the Peterhead boat is being reviewed, BBC Scotland has learned.
Widows travelled to Downing Street to protest against the plan
Authorities want to establish why the Trident sank in 1974 off Caithness with the loss of seven crew.
Evidence that led to the nature of the survey being decided is to be scrutinised by the advocate general.
Some families who instead want the wreck lifted have welcomed the news of the review.
Many of the families of the seven men lost on the Trident say that the underwater survey would desecrate the graves.
Widows who lost their husbands appealed directly to Prime Minister Tony Blair to halt plans to cut the wreck open when they travelled to Downing Street on Tuesday.
Jeannie Ritchie, her 90-year-old mother Mary Nicol, Irene Summers and Valerie Thain handed in a file on the case.
Next week a diving vessel paid for by the Department for Transport is due to start the underwater survey.
The advocate general's decision to review the evidence does not mean the operation will be abandoned, but relatives welcomed the review.
Mrs Ritchie, 65, who lost her husband and father, said they would take legal action to stop the survey.
Widow Mary Nicol, 90, travelled to Downing Street
She said: "Our plea to Mr Blair is to stop the Department for Transport and the advocate general for Scotland proceeding to the wreck of the Trident to cut the vessel open on the seabed.
"We want Mr Blair to intervene and we are also seeking to stop the survey going ahead.
"By doing so, they will lose all the vital evidence on how the Trident sank and it would desecrate the men's graves.
"They should lift the vessel and test it, and those who wish to bury their dead can do so while the others can be returned to the sea."
Mrs Ritchie said the widows were prepared to fight all the way to the European Court of Human Rights if necessary.