The telegraph should be ashamed of such bald-faced propaganda

Of course, Israel won't believe that because Israel managed to conceal a weapons plant underneath their reactor at Dimona, and Israel will never admit that other nations do not behave the way Israel does. Hence, if Israel does it, Iran must be assumed to be doing the same.
The IAEA which has full access to Iran's nuclear facilities confirms the work is about building a power station and no indications of a weapons program anywhere to be found.