Calls for a fresh inquiry into the 7/7 attacks have grown after it emerged MPs were not shown photographs linking one of the bombers to known militants.
The Intelligence and Security Committee probing 7/7 did not see all of the pictures taken in 2004 showing Mohammad Sidique Khan with terrorist suspects.
Shadow home secretary David Davis said there was a fear "that someone was being economical with the evidence".
Data released after the fertiliser bomb plot trial has sparked the controversy.
Security sources say MI5 said it did not reveal the images to the parliamentary committee because they were taken by police officers not MI5 operatives.
On Monday, it emerged at the end of the year-long court case that MI5 had watched and followed two of the 7 July bombers a year before the attacks as part of their surveillance of the fertiliser bomb plotters.
By June 2004 MI5 had part of Khan's name on file twice, a family address and various pictures of him.
The ISC committee investigating 7/7 only ever saw one MI5 photograph of Khan. It did not see any of the other photographs obtained by the BBC. A senior Whitehall source has told the BBC that the committee were aware other pictures existed and could have seen them if they had been requested.
Mr Davis said: "What is clear is that there is a massive difference between what the public know and the impression given by the ISC report last year.
"We must have an inquiry which allows us to know what the facts are and not feel, as we might do today, that we have been misled."
Jacqui Putnam, who survived the Edgware Road bomb, also called for an inquiry, saying it was "inevitable" the truth would come out.
"I do not understand why they lie so inadequately to cover up these things. It is disrespectful, it seems to me, to the people who died and the families who are struggling to live with it," she said.
Ministers are opposed to an inquiry but a parliamentary committee will consider why the bombers were not picked up.
Those affected by the 2005 attacks have delivered a letter to the Home Office.
The document, requesting an "impartial public inquiry", was handed to an official from the department.
It says one of the purposes would be "to examine issues aimed at saving lives, minimising suffering and improving the response of government agencies to the continuing threat of terrorist attacks".
The letter was signed by more than 18 people, including 7 July survivors Ms Putnam and Paul Mitchell, as well as relatives of those affected - such as Ros Morley, whose husband, Colin, was killed.
Survivor Rachel North said: "This is not about blame but about future public safety - understanding what happened, how it happened and to stop it happening again."
In response, the Home Office released a statement saying the home secretary would "give very careful consideration" to the letter.
On Monday, five men were given life sentences for a foiled plot to build a huge fertiliser bomb for a UK attack.
It emerged during the trial that MI5 had tailed London suicide bombers Mohammad Sidique Khan and Shehzad Tanweer while investigating that case, but took no action.
The BBC has now published a full transcript of an MI5 bugged conversation in which the bomber discusses leaving the UK to join jihadi extremists in the Pakistan-Afghanistan border areas.
The media were briefed that Khan and fellow bombers were "clean skins" - men with no previous record of terrorist associations.
The row has taken the shine off the conviction of the five men
But evidence following the end of the trial reveals MI5 photographed Khan as he met other extremists, followed him home - and by the summer of 2004 they knew his surname and that he owned a car.
Prime Minister Tony Blair has asked the parliamentary Intelligence and Security Committee (ISC) to consider why the 7 July bombers were not picked up.
The committee, which comprises MPs and Lords, is expected to examine claims that West Yorkshire Police special branch was not told about the MI5 surveillance operation.
ISC chairman Paul Murphy MP has previously indicated that police were informed.
WHAT MI5 TOLD COMMITTEE
We have been told in evidence that none of the ... 7 July group had been identified (that is named and listed) as potential terrorist threats prior to July
ISC report into MI5, 2006
The revelation that one of the 7 July bombers met up with one of the fertiliser bomb plotters - Omar Khyam - at a terrorist training camp in Pakistan has caused concern.
However, the head of Pakistan's National Crisis Management Centre, Brigadier Javed Iqbal Cheema, said anyone "who spends a lot of money and travels to Pakistan...[is] already motivated for a particular reason".