The inquests into the deaths of 52 people in the 7 July bombings in London will examine the roles of the police and intelligence service MI5 before the attack.
Coroner Lady Justice Hallett said it was 'not too remote' to investigate what was known in the years before the atrocities took place.
Lady Hallett also told the Royal Courts of Justice that inquests into the deaths of the four suicide bombers will be held separately from those of the victims and that she will sit without a jury.
She said: 'The scope of the inquest into the 52 deaths will include the alleged intelligence failings and the immediate aftermath of the bombings.
'To my mind it is not too remote to investigate what was known in the year or two before the alleged bombings. Plots of this kind are not developed overnight.'
Lawyers for the bereaved families wanted the upcoming hearings to include a broad-ranging investigation into whether police and the intelligence services could have prevented the attack.
The inquests have been delayed by court cases connected to the 2005 bombings.
Suicide bombers Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, Hasib Hussain, 18, and Jermaine Lindsay, 19, met at Luton station on the morning of 7 July.
They took a train to King's Cross in London, before separating to carry out their deadly attacks.
Within three minutes of 8.50am, Tanweer detonated his bomb at Aldgate, Khan set his device off at Edgware Road and Lindsay blew himself up between King's Cross and Russell Square.
Hussain detonated his device on board a bus at Tavistock Square at 9.47am.
As well as killing themselves and 52 others, the bombers injured more than 700 people.
The 7 July inquests are expected to take place in a courtroom at the Royal Courts of Justice, starting in October.