Don't forget that you are taxed on ALL income earned in the calendar year on a 'cumulative' basis. Therefore, if you have been earning for the first half/ two-thirds of the year you will likely be paying tax on earnings, even though your more recent earnings will be much lower than your earlier earnings.
It's likely that the tax adjustments arising due to your drop in income (you might have been paying tax at 41% earlier in the year if your income was high enough but now with the drop are unlikely to be doing so; hence your average tax rate should decline) will probably be sorted out by your payroll office before December 31.
If in doubt, you can ask the tax office for a 'Balancing Statement' after December 31 for the 2009 tax year.