Maternity leave, tax codes and company car.

[chickenfactory]

I'm going on maternity leave soon and just got a new tax code in of 247L, I owe around £400 from being on the wrong tax code due to changing cars so they are claiming some back over the next year.

Obviously HMRC dont know I wont be on full pay. I earn £23k and get 18 weeks full pay, 21 weeks SMP. I get to keep the car during maternity leave so my tax code will still be low.
Is SMP taxed on this code? If so how do I work out what I'll get in hand? I'm not planning on going back for a number of reasons, and will probably be SAHM for a while.

If they havent claimed back the full £400 will I get a bill at the end of the tax year? I need to speak to HR about giving the car back, although no-one else seems to ever have (whether they came back or not) - so I dont know what the status quo would be for this.

Is that the code for 2012/13 or 2013/14? I'm going to assume that it is for 2013/14, you start your maternity leave at the beginning of the year, and 18 weeks works out as exactly 5 months.

For 5 months you will get £1,422pm then SMP at £136.80pw (this rate is not confirmed yet) which should work out at an average of £500pm for 5 months, although it might be a bit higher than this at the start depending on exactly where paydays fall etc.

If you don't go back to work you will almost certainly end up OVERpaying tax for the year so you will need to ring HMRC to sort this out once you have received your final pay.

Thanks Mr Anchovy

Sorry, "18 weeks works out as exactly 5 months" is obviously rubbish, you should get an average of £500pm for FOUR months, making 9 months (39 weeks) of maternity pay in total