Contact your local library. This is what mine says about this:
"There is a charge of £8.50 to request an inter-library loan, which must be paid even if the item cannot be supplied. If an item is supplied by the British Library or an academic library, this will have a charge of £20.60. Please see our webpage on fees and charges for more information. This process can take 6 weeks or longer."
However, the page does also say:
"The British Library are experiencing a major technology outage as a result of a cyber-attack. The outage is affecting their website, online systems and services, which means we are not able to request inter-library loans from them at the moment."
Whether that last bit is up to date or not I don't know.