THE 7/7 bombers evaded detection by buying unregistered pay-as-you-go mobile phones which they used for only a few weeks before dumping them, an inquest heard yesterday.
A police expert said the four employed "tradecraft" counter-surveillance techniques to ensure their communications were not intercepted.
They each bought "operational" phones, which they kept separate from their personal mobiles and used solely for planning the July 7 2005 London bombings, the hearing was told.
From May 2005 until the attacks, bombers Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, and Hasib Hussain, 18, used four different phones and Jermaine Lindsay, 19, used three.
Detective Sergeant Mark Stuart, a Metropolitan Police expert in telecommunications data, told the hearing that mobiles belonging to Khan, Hussain and Lindsay were recovered from the bomb sites.
Police were able to recover data from Lindsay's phone, including the SIM card number and text messages that he received and sent.
The inquests have heard that the terrorists might have originally planned to carry out the bombings 24 hours earlier, when the capital was due to learn whether it had won the 2012 Olympic Games.
Plot ringleader Khan visited Dewsbury Hospital in West Yorkshire with his wife, Hasina Patel, on July 5 because of complications with her pregnancy.
Khan apparently postponed the planned attacks in a text message to Lindsay at 4.35am on July 6 which read: "Havin major problem cant make time will ring ya when i got it sorted wait at home."
On the morning of July 7, Khan, Tanweer, and Hussain drove from their bomb factory in Leeds to Luton railway station, where they met up with Lindsay and caught a train to London.
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 the number 30 bus at Tavistock Square nearly an hour later.
Altogether 52 people were killed and more than 700 injured in the attacks, the worst single terrorist atrocity on UK soil.
DS Stuart said the four bombers displayed "tradecraft" in their use of mobile phones.
He defined this as "taking care over your communications, buying pre-paid unregistered phones, changing them regularly to avoid detection".
Referring to the operational phones, he said: "Apart from calls to each other, the only other calls made were to car hire companies, including the car hire company that was eventually used for the Nissan Micra left at Luton railway station on the 7th."
The inquests also heard that Scotland Yard made nearly 4,500 requests to phone companies for information as part of the massive investigation into the July 7 attacks.
Footage of one of the July 7 attackers calmly rummaging around in his rucksack bomb as commuters walk nearby also played at the inquests,
Hasib Hussain, 18, was captured on film walking around London's King's Cross station before boarding a number 30 bus and killing himself and 13 others in Tavistock Square.
Investigators compiled footage tracking him emerging from the Tube, joining others trying to escape the chaos and wandering around the busy concourse.
In extraordinary footage, Hussain can be seen pausing in the doorway of a branch of WHSmith for two-and-a-half minutes to apparently remove a battery from his device.
He buys a 4.49 9-volt replacement and heads to a nearby McDonald's, where police believe he spent eight minutes putting the new battery into the bomb.