brits knew it was coming?

this is a very disturbing bit of information about the london terrorist attacks. the british police called the israeli embassy and advised the security detail there that they had warnings about terrorist attacks about to occur. benjamin netanyahu consequently did not attend the economic conference taking place directly above one of the underground stations that was hit.
this makes me angry, and i would definitely like to know more. what did they know, and when did they know it? i will withhold comment until those questions are answered, which i am sure will not be any time soon.
UPDATE: israeli embassy is denying there was advance warning.