Quote from MrPowerBallad:
Something to consider for his timing -- he's either going to hold an election in late March or early May -- the IMF report is due sometime in April -- his opponent has called the tax âliterally hopelessâ -- even if the report comes back favorable for the tax, Brown might not be around to follow through.
According to an article posted a little earlier:
http://www.efinancialnews.com/investmentbanking/content/1056027739/
"The IMF is due to report to the G20 on how the financial sector should make a contribution toward paying for government intervention next year with a preliminary report due in April and the final report due in June.
A spokesman for the Treasury confirmed that the UK would not act on any policy related to a transaction tax until after the final report, by which point a general election will have been held in the UK. "