What is a "PO" in an invoice for payment?

faringdon

Hi,
I have just emailed accounts at the engineering company where i work as a Sole Trader (Electronics Engineer). I asked them who i should address the invoice to and when i should send it in the month (we are to be payed monthly).
However, i just got an automatic replay saying..........

QUOTE>>>>
Acme engineering operates under a "No PO, no pay" policy. To ensure your invoice is paid without delay, please clearly quote the PO number on the invoice copy. Failing this, please quote the PO number in the email subject. (Acme engineering PO numbers begin with PF.) 
>>>>>>UNQUOTE

Do you know what the above means? Please advise? I wasn't aware you had to put a "PO" (Purchase order?) on an invoice for monthly pay?
I started working there on 12th November 2025. In my  employment contract, it just said that my pay would be "monthly in arrears" and nothing else was stated.

Grumpy_chap

PO = Purchase Order.

The customer requires their PO number to be quoted in your invoice so that they can reconcile to the correct cost centre and the correct individual to confirm Goods (Services) Received and authorised payment.

Jude57

faringdon said:

Hi,
I have just emailed accounts at the engineering company where i work as a Solde Trader (Electronics Engineer). I asked them who i should address the invoice to and when i should send it in the month (we are to be payed monthly).
However, i just got an automatic replay saying..........

QUOTE>>>>
Acme engineering operates under a "No PO, no pay" policy. To ensure your invoice is paid without delay, please clearly quote the PO number on the invoice copy. Failing this, please quote the PO number in the email subject. (Acme engineering PO numbers begin with PF.) 
>>>>>>UNQUOTE

Do you know what the above means? Please advise? I wasn't aware you had to put a "PO" (Purchase order?) on an invoice for monthly pay?
I started working there on 12th November 2025. In my  employment contract, it just said that my pay would be "monthly in arrears" and nothing else was stated.

I agree that it's likely to mean Purchase Order but suspect that, unless you're employed to provide a specific number of widgets which is ordered each month, there'll be a different mechanism in place to pay contractors who are employed provide their skills rather than an actual, physical product. My late partner was such a contractor and he had to send his invoices direct to  the person who authorised them, using a separate email address and a PO number created, with associated cost centre, specifically for him. The month's invoice was reconciled to his timesheets, authorised and paid. The company you're contracting for will probably have a similar system.

My guess is that an automated system isn't set up to pay contractors because it can't automatically authorise payment for the time you're claiming. I'd suggest speaking to whoever approves your timesheet  asking them how to proceed. In the unlikely event that they don't know, speak to someone in Payroll because unless you're the first ever contractor, they'll have dealt with this scenario before. If you still get no joy, it's time to speak to a Director but hopefully you'll be sorted before you need to do that.

Caz3121

If you started 12th November are you due to submit your first invoice on 11th December for that month or have you been advised to submit a part month's invoice at the end of the calendar month?
I suspect that you have not been advised of the Purchase Order number yet to use as there is no invoice due yet

Grumpy_chap

Caz3121 said:

If you started 12th November are you due to submit your first invoice on 11th December for that month or have you been advised to submit a part month's invoice at the end of the calendar month?
I suspect that you have not been advised of the Purchase Order number yet to use as there is no invoice due yet

It is not unusual when working on contract basis to submit time-sheets / invoices on a weekly basis.  That is common when via an Agency, even if the work is outside IR35, the payment route can be via an Agency.  Invoices are increasingly processed on a self-billing basis in this arrangement so the individual only has to obtain timesheet approval and the invoice and payment is then taken care of by the Agency.

In my experience, when working on a contract basis and invoicing end-Clients directly, the invoice is raised either on completion of a defined task or at (financial) calendar month-end.

I wonder whether the OP was correct to invoice the end-Client or should have been invoicing via an Agency.

GardenBirdWatcher

I wonder whether the OP was correct to invoice the end-Client or should have been invoicing via an Agency.

Going on the OP's previous threads, we can't even be sure he's actually a contractor and not an employee on a fixed-term contract

EnPointe

GardenBirdWatcher said:

I wonder whether the OP was correct to invoice the end-Client or should have been invoicing via an Agency.

Going on the OP's previous threads, we can't even be sure he's actually a contractor and not an employee on a fixed-term contract

or some one tryingto train an LLM or  indeed someone whose abode is under a rickety bridge