I am a sole trader who keeps his van at my home for security purposes, as the area where my shop is located is much more subject to vehicle crime than other areas of the town. The van is sign-written with my business name and used for transporting stock etc. during the day, and then taken home at night. Shop to home is now approximately a 25-mile round trip, as I recently moved to a new house, whereas before it was only a 4-5 mile round trip. Can the commute between home and shop be treated as a business expense due to these security reasons?

If you look at www.gov.uk/hmrc-internal-manuals/business-income-manual/bim37605 and www.gov.uk/hmrc-internal-manuals/business-income-manual/bim37935 you can see that in principle travel from home to work for a sole trader is not an allowable expense. The fact that you also have the security of your van in mind would probably be answered by HMRC that there is a 'duality of purpose' here, but nevertheless, this is essentially a private journey.