If the invoice remains unpaid

This may sound extreme, and definitely shouldn’t be used lightly, but if you have a real fear that the invoice will not be paid or that the company owing the invoice may go into administration then you are technically working for free. The purchaser of your services is also in breach of contract if they are not paying an invoice within the time stated in your contract for services.

However, only you will know if this is the correct course of action and it should only be used with caution and with proper advice.

If you believe that the invoice will eventually be paid and that such action isn’t immediately necessary you could try to use the late payment legislation.