For over 30 years, politicians from Israel and the US have said that "Iran will have a nuclear weapon in less than a year". [Christian Science Monitor timeline of these warnings]
Some more examples:
For: USA Today, Sep 2008
By April 2012 Iran will have five nuclear bombs or warheads, says intelligence reaching US president Barack Obama and relayed to Jewish leaders at a closed meeting in New York Sunday, Nov. 13, debkafile's sources report.
Against: Media Matters
For: IranWatch, April 2012, which actually gives some more detail estimates of their progress, which seem consistent with the International Atomic Energy Agency's reports on Iran.
I do not have a nuclear engineering degree, but the timelines seem to based on the time taken to produced highly enriched uranium. It's hard for me to know how much time enriching this uranium takes. IranWatch (see above) claims 3-12 months.
My question is twofold:
Could Iran enrich their 20% uranium to 90% in under 12 months?
Alternatively, could they make a nuclear weapen with 20% uranium in under 12 months?
Note: I am in no way suggesting that Iran is seeking to build a nuclear bomb. The question is whether the hypothetical estimates provided are feasible.