IHTM30183 | Payment methods: payment by national savings or government stock

From HM Revenue & Customs · Inheritance Tax Manual

To pay by national savings taxpayers should use the following guidance

https://www.gov.uk/paying-inheritance-tax/deceaseds-bank-account

To pay by government stock taxpayers should use the following guidance

https://www.gov.uk/paying-inheritance-tax/british-government-stock.