VATGPB5235 | Police authorities: specific activities: escort of property and abnormal loads
From HM Revenue & Customs · VAT Government and Public Bodies
For reasons of public safety, highways and road traffic legislation require the police to escort abnormal or hazardous loads - for example escorting the transport of nuclear material. In these circumstances any charge is considered to be non-business. However, escorting other property, for example movements of bullion for the Bank of England, is theoretically undertaken in competition with the private sector and so is a standard-rated business supply.