Israel almost never takes responsibility for mysterious killings in the Middle East. To do so would only cause diplomatic and security problems and reveal operational methods.

As it is, most of the targets have multiple enemies and whoever's finger was on the trigger, Israel will be blamed.

There is one major exception to this rule: sometimes things go dramatically wrong and the only way to release a captured agent is to own up.

Did the assassins who eliminated the Hamas arms smuggler, Mahmoud al-Mabhouh, mess up? Operationally, no.

The target is dead, probably after giving up vital information; all members of the team left Dubai without being detected; and for the first two weeks after his death, Hamas were still not convinced he hadn't had a heart attack.

The ten men and one woman captured on CCTV cameras seemed to be acting professionally and the fact that their passport photos were broadcast around the world is of little consequence. They will have no problem assuming new identities.

There can be no doubt the planners knew that every corridor in the hotel was covered by CCTV. But it does not appear they realised the security services in the emirate would be so adept at utilising face-recognition technology and connecting the rather blurry images of the team in the hotel with their passport photos which were scanned at Dubai International Airport.

The fact that at least half the team were travelling under the assumed identities of Israeli citizens, most of whom emigrated from Britain, is reminiscent of episodes in which Mossad is known to have used the identities of Israelis with dual citizenship. It is the first real piece of information that could link Israel to the operation.

When the assassination became public, a few Israeli ministers found it hard to conceal their satisfaction, but there has still not been any official denial.

And there probably won't be. Two former Mossad officers - Rafi Eitan and Rami Igra - did the rounds of TV and radio on Wednesday. Both said this could not have been the work of the organisation - but they are not spokesmen.

If they are telling the truth, questions will have to be asked in Israel, Britain and Germany over the vulnerability of databases. If it was Mossad, thornier issues will have to be addressed.

On an operational level, the leaders of Israel's defence establishment will have to ask themselves why, once again, did senior intelligence and operations officers severely underestimate Arab capabilities.

Another question is why the service continues to use identities of innocent Israelis and diaspora Jews, which can increasingly easily be tracked down and cause these people major problems in the future.