Thompson: 'The cyber-attack on the BBC is not the first we have experienced'Credit: Lee Jordan on Flickr. Some rights reserved.
Speaking at the Royal Television Society last night, Thompson said the broadcaster was "taking every step we can" to ensure that services are not affected "by those who seek to disrupt or block" BBC reporting.
The corporation has complained repeatedly of satellite jamming and intimidation of staff and family members at the BBC Persian service.
Thompson said: "It now looks as if those who seek to disrupt or block BBC Persian may be widening their tactics. There was a day recently when there was a simultaneous attempt to jam two different satellite feeds of BBC Persian into Iran, to disrupt the service's London phone-lines by the use of multiple automatic calls, and a sophisticated cyber-attack on the BBC.
"It is difficult, and may prove impossible, to confirm the source of these attacks, though attempted jamming of BBC services into Iran is nothing new and we regard the coincidence of these different attacks as self-evidently suspicious.
"The cyber-attack on the BBC is not the first we have experienced. For millions of Iranians, BBC Persian is a precious source of reliable information about what is happening in the world and in their own country.
"I don't want to go into any more detail about these incidents except to say that we are taking every step we can, as we always do, to ensure that this vital service continues to reach the people who need it."
Thompson added: "The Iranian equivalent of Ofcom put it best when they compiled a report about the BBC's new service a few months after launch.
"In summary, the report acknowledged that the Persian service seemed to be making every effort to be truthful and fair-minded. That, they said, is why it is so insidious."
New figures released last month reveal that the BBC Persian service has almost doubled its audience in two years, from 3.1 million in 2009 to six million last year.
The BBC has complained of deliberate interference with the Persian channel's broadcast signals - since the service launched three years ago. Last December, five international broadcasters issued a joint statement calling on regulators to take action against those responsible.