Can my employers extend my notice without me knowing?

[aorr_bcn]

I handed in my notice to my manager and we agreed on a date for me to leave, 23rd october.
I agreed with my new empolyer a date to start on the 25th October.
However I found out a few days ago, when I spoke to my new employer, that my current employer had contacted her and told her my notice period had been extended and that I can't start with her until November. My current boss hasnt told me this yet. He hasnt contacted me about my notice period let alone extending it.
Is he allowed to extend it without consulting me?
What should I do?

[buildersmate]

If you gave at least your contractual notice to your employer, the employer has absolutely no right to ask or force you to extend it. Absolutely.
If you handed in your notice and came to mutual agreement with your employer that you would leave before the expiry of your contractual notice period, then it has got messy. The way I would stop being messed around for sure would have been to have dropped an email saying ' dear boss, as we discussed I will leave on 23rd Oct'.
It is basically your word against his, but I would stick to your guns. The fact that he has contacted your new employer first before talking to you suggests something underhand on his part. It is the end of the day, there is nothing he can do to stop you leaving - just make sure your new employer know what an inreasonable man your current boss is.
He cannot deny you your pay and benefits - just threaten action at an Employement Tribunal to reclaim your denied wages if he does.