Iranian missiles could do a lot of harm in case Israel would attack

 On 24 March 2012 some 1000 Israeli's demonstrated in Tel Aviv against a possible Israeli attack on Iran (Photo Dahlia Scheindlin, +972 Mag)

The Lobelog, the blog of Jim Lobe of IPS, is one of those places that one should keep an eye on in order to be well informed.  On 29 March it carried an article by Gareth Porter, a journalist who specializes in U.S. National security, based on an interview with on of Israel's leading experts on Iranian missiles and the head of its missile defence programme for nearly a decade. He contradicts the optimistic scenario as portrayed by the Israeli government that says Iran is to weak to effectively react to an attack. On the contrary,  Iranian missiles are capable of doing significant damage to Israeli targets.

....Uzi Rubin, who was in charge of Israel's missile defence from 1991 to 1999 and presided over the development of the Arrow anti- missile system, has a much more sombre view of Iran's capabilities.
The "bad news" for Israel, Rubin told IPS in an interview, is that the primary factor affecting Iran's capability to retaliate is the rapidly declining cost of increased precision in ballistic missiles. Within a very short time, Iran has already improved the accuracy of its missiles from a few kilometres from the target to just a few metres, according to Rubin.
That improvement would give Iran the ability to hit key Israeli economic infrastructure and administrative targets, he said. "I'm asking my military friends how they feel about waging war without electricity," said Rubin.
The consequences of Iranian missile strikes on administrative targets could be even more serious, Rubin believes. "If the civilian government collapses," he said, "the military will find it difficult to wage a war."
Rubin is even worried that, if the accuracy of Iranian missiles improves further, which he believes is "bound to happen", Iran will be able to carry out pinpoint attacks on Israel's air bases, which are concentrated in just a few places.

Some Israeli analysts have suggested that Israel could hit Iranian missiles in a preemptive strike, but Rubin said Israel can no longer count on being able to hit Iranian missiles before they are launched.
Iran's longer-range missiles have always been displayed on mobile transporter erector launchers (TELs), as Rubin pointed out in an article in Arms Control Today earlier this year. "The message was clear," Rubin wrote. "Iran's missile force is fully mobile, hence, not pre-emptable."
Rubin, who has argued for more resources to be devoted to the Arrow anti-missile system, acknowledged that it can only limit the number of missiles that get through. In an e-mail to IPS, he cited the Arrow system's record of more than 80 percent success in various tests over the years, but also noted that such a record "does not assure an identical success rate in real combat". 

 and 

Gen. Gabi Ashkenazi, then IDF chief of staff, told a visiting Congressional delegation in November 2009 that Iran already had 300 missiles capable of hitting Israeli targets, according to a U.S. State Department cable released by WikiLeaks.
Those reports suggest that Iran now has roughly 450 missiles that can reach Israel, half of which are improved models with much greater precision. Even if only one-fifth of those missiles get through Israel's missile defences, Israeli cities could be hit by at least 100, most of which are able to hit targets with relative accuracy. 

The whole article can be found here