National Nuclear Laboratory

Invoicing for Goods or Services

NNL are committed to paying our Suppliers in line with the Government’s Prompt Payment Policy:

Where goods/services are not paid for using a Company Credit Card (Purchasing Card) NNL operate a three-way matching system, which enables goods and services to be ordered, receipted and paid for through our Business World system. This means that as long as your Invoice contains the same information (price, quantity etc) as the Purchase Order, and the person who has received the goods/service has confirmed this, your Invoice will automatically be processed through to the next payment run.  However, if any of this information is missing it could cause delays as the Invoice will be classed as “disputed”. It is therefore important that the following principles are adhered to when accepting an order from NNL.

  1.  Do not accept any orders without an NNL Purchase Order number. Every order must have a valid Purchase Order number. If your Invoice does not quote a Purchase Order number, it will be returned to you. Our order number format is a 7 digit which will begin with either 1 (for services) or 7 (for goods).
  2. Do not accept telephone orders unless they are being paid for immediately by Credit/Purchasing card. Company cards are widely used throughout the business and are a perfectly valid way of ordering and paying for goods, however; do not accept telephone orders unless they will be followed up by an emailed/posted Purchase Order immediately afterward – and always asked for the Purchase Order number if this is the case.
  3. Ensure that your Invoice contains the correct delivery quantity. This is especially important where partial deliveries are made.
  4. Ensure that your Invoice identifies clearly the order line that the cost refers to. Where the order contains multiple lines, it is sometimes difficult to corelate the PO to the Invoice, please do everything you can to make sure this information is clear.
  5. Credit notes must be provided where applicable. Credit notes should clearly show the Purchase Order Number, Purchase Order Line number (for multiple line orders), the quantity and value of the credit.
  6. All Invoices must be sent electronically to Do not send your Invoice to the person who placed the order, or to an individual within NNL as this will cause delays. In the event that you cannot provide an electronic Invoice, post the Invoice to:

Accounts Payable
National Nuclear Laboratory
Chadwick House

Any queries on your payment must also be sent to the email address, or postal address above. Please do not contact individuals as this may lead to delays getting to the right person.