The question whether the London attacks were done by suicide bombers or instead by bombs on timers is an interesting one. The early suspicion that they were suicide bombings quickly changed to a tentative consensus that the bombings were on timers, the primary evidence being that the 3 bombs in the Underground were exploded within a minute of the others.

On the day after the bombing, Debka.com took a different view on several points:

The bombing attacks on London's Underground railway and a double-decker bus Thursday, July 7, were the work of a team of 6-8 terrorists wearing explosive vests.

This is the first conclusion drawn by DEBKA-Net-Weekly's terror experts from the type and strength of the explosives used and they way the bombers, in three out of the four attacks, were able to deliberately spread the damage to secondary vehicles outside their primary targets.

The explosion on the trains at Kings Cross and Edgware Road stations--and the bomb that wrecked the bus at Tavistock Square--were also aimed at hitting passing trains and cars to maximize the casualty toll. To accomplish this, the bomber needed to watch out for moving vehicles and judge the exact moment for detonating the explosive with zero chances of surviving the blast.

The bombs were not large, smaller than the ones that were planted on the Madrid trains in March 2004, because they had to be worn on the terrorists' bodies without arousing suspicion. In Madrid they were left in bags.

At the big Kings Cross station, two trains were caught in the blast; at Edgware Road station, three trains were hit.

As for the bus, two suicide bombers sat at the back of the bus well separated, ready to detonate their vests as soon as they saw a second bus came close through the rear window. They then both tripped the cords on their bombs. The bus's upper deck was ripped off and hurled in the air. Had there been one bomber, only one side of the bus would have been wrecked. . . .

More than a few British Muslims have spent time in Arab countries studying at religious institutions whose curriculum includes military training and bomb-making instruction.

Two such British Muslim suicide killers, Asif Mohammed Hanif and Omar Khan Sherif, were dispatched to Tel Aviv to blow up the American embassy on April 30, 2003, When they saw the building was a fortress, they switched to an attack on the neighboring Mike's Bar.

A joint British-Israeli probe traced the two bombers' movements from London to Damascus where they studied and were recruited at a medressa run by al Qaeda's adherents. The pair picked up their bomb vests from Hizballah agents in the Gaza Strip which they entered as British tourists supporting the Palestinian cause.

The London bombers' modus operandi recalls that of Hanif and Sherif two years ago.

I considered blogging it at the time, but Debka's version of events was so different from what most were saying (and the certainty with which some of their speculations were presented was so unjustified) that I thought that I'd wait to see if anything checked out. Now some of Debka's more unusual ideas are being echoed in a few other stories, though there is still no evidence mentioned by others pointing to the bombings in the Underground being the work of suicide bombers. The bus bombing, however, may have been either a suicide bombing or an accidental detonation.

The Times (London):

It is understood that the examination of the No 30 bus at Tavistock Square has yielded vital fragments that have sharpened the focus of the police inquiry. Forensic pathologists have been paying particular attention to the remains of two bodies found in the mangled wreckage of the double-decker.

A senior police source said: "There are two bodies which have to be examined in great detail because they appear to have been holding the bomb or sitting on top of it. One of those might turn out to be the bomber." A decapitated head was found at the bus scene which has been, in Israeli experience, the sign of a suicide bomber.

The Australian:

The revelation came as it emerged that the severed head of a man had been found near the bus torn apart at Tavistock Square in the London bombings, strengthening suspicions that a suicide bomber was behind the blast. Suicide attacks in Israel have shown that a head is often the only remnant of a suicide bomber, as an explosion close to the torso can force the head to fly up, remaining intact while the rest of the body disintegrates.

London's Daily Telegraph reported yesterday that the head found near the bus had almost certainly been blown out of the upper deck where a rucksack-sized bomb is believed to have been planted on a seat. The head may be that of an innocent passenger who picked the bomb up just before it exploded, but police have believed from the start that the bus could have been hit by a suicide bomber. . . .

One passenger who got off the bus just before the explosion had noticed a nervous young man behaving oddly on the bus and frequently dipping into a bag at his feet.

Investigators are convinced three other terrorists escaped after leaving bombs on three Underground trains about 47 minutes before the bus blast.

Arutz Sheva:

Israel police have revealed that the explosives used in the multi-pronged terrorist attack in London last week were materially identical to the explosives used by two British Muslim suicide bombers who struck in Tel Aviv more than a year ago.

It is unknown at this time if the apparent explosives link points to an Israel-based connection, or if it points to a common source of materiel outside both the UK and Israel.

One of the two bombers, who had entered Israel on authentic British passports, blew himself up in Mike's Place pub in the city, killing three people.

The Telegraph:

Police believe one bomber blew himself up, possibly accidentally, on the upper deck of the bus, in Tavistock Square, and are trying to establish whether a head found nearby was that of a suicide bomber. Decapitation is a classic effect in suicide bombing where explosives are packed close to the torso.

SKY NEWS:

Richard Jones, who was travelling on the packed Number 30, said he is convinced he saw a bomber on board setting a device.

The 61-year-old told The Sun: "I noticed him as he looked nervous. He was continually diving into his bag, rummaging round and looking in it."

Seconds after Mr Jones stepped off the bus, it exploded with the "bomber" still on board. Terence Mutasa, 27, a staff nurse at University College hospital, told The Sun: "I treated two girls in their 20s who were involved in the bus bomb.

"They were saying some guy came and sat down and that he exploded."

He added: "They said the guy just sat down and the explosion happened. They thought it was a suicide bomber."

Israel Insider:

The terror attack in London last week may be tied to a suicide bombing on Tel Aviv's beachfront in April 2003, German newspaper Bild am Sonntag reported.

According to the paper, Mossad officials informed British security officials that the explosive material used in the Tel Aviv attack on Mike's Place pub was apparently also utilized to stage the bombings in London on Thursday.

Cape Times:

Authorities said a fresh analysis of data from eyewitnesses and the Underground's computer and electrical systems showed the three blasts occurred within 50 seconds of one another, starting at 8.50am.

Deputy Assistant Commissioner Brian Paddick said at a Metropolitan Police briefing that authorities had not ruled out the possibility of suicide bombers but now believed it was more likely the attackers had used timers.

Michael Oren of the Shalem Centre panel in Jerusalem agreed. "In Israel, we've had co-ordinated suicide bombings but they've never been that close," he said. "If they've got down to a minute that would be an all-time record."

Paddick said no timing devices or other detonators had yet been discovered in the wreckage. When they are found, they are "probably going to be in millions of pieces", he said.

He said early analysis suggested that each bomb consisted of a "device in a bag, rather than something that was strapped to the individual".

A string of stories are now saying that the explosives are of the same type as was used in the Mike's Place bombing in Israel. Some of the stories tend to support there having been a suicide bomber on the bus, and one story even raises the possibility of two bombers on the bus, though the bombs are still believed to have been in bags rather than strapped to bodies. My conclusion is not that Debka is right about any of this, but rather that we should wait for evidence before jumping to conclusions on what happened. The conventional wisdom can change as new evidence is sifted through.

UPDATE (Tuesday): Several UK media outlets are now saying that the London bombings were the work of suicide bombers (tip to Instapundit).