How long would you expect to have to wait for P45 ????

He should contact his old job and ask for it

Yes he will be emergency taxed until he gets it

? I thought he should have it. Will get in touch with previous employer asap x

He should have his P45 with his last payslip. He will be on "emergency tax" as it used to be called - the thing is that there are two sorts, one with allowances and one without any. Make sure that the agency has got him to sign the P46, which means that he will still get a tax allowance but not a rebate; if they fill it in without getting him to sign it he won't get any allowances until things are sorted out.