I am about to go on maternity leave and wish to continue with my salary sacrfice towards my son's childcare. though my salary will be only SMP. I heard a rumour that somehow my employer have to contirbute to this - is this true? - in which case, can someone point me in the right direction re more info - I find the HM revenue website impossible to navigate
Here is the HMRC official guidance which you can pass to your employer if you have problems.
Your employer is not allowed to make salary sacrifice deductions from SMP as you will see from this guidance. However as your childcare vouchers are a contractual benefit, your employer must continue to provide you with vouchers as normal during your maternity leave. So effectively you are getting paid a chunk of your childcare costs by your employer during your maternity leave.