Company withholding p45 can they do this ?

I started a new job this week finished up in old job last week. Payroll in new job closes Friday and I will be on emergency tax if I don't hand in my P45 by then. Old employer won't send out*my P45 to me until after the 24th which is payday. Payroll has already been done in old job so can they withhold my P45 like this?

Contact your local Revenue department and they will send you a new Tax Credit Certificate so as you don't have to pay emergency tax. They will ask you for your new employers registered tax number....someone in payroll will be able to give it to you.
Tell who ever your talking to in revenue what's happened and they will put a hurry on it for you.

Its normal for them not to send out the P45 until after you are paid for the last time. Nothing is going to change but its just what people do

As above ring revenue and ask for a Week1 cert to be sent to new employer.