Driven by the Queen, the Daimler Super V8 LWB limousine was in royal ownership from 2001 to 2004.
Being sold with its original documentation and with photographs of the Queen driving it, the four-litre engined car is being auctioned by classic car auction specialist Historics at Brooklands at Brooklands Museum in Surrey on August 31.
Likely to fetch between £25,000 and £30,000, the Daimler was taken on 2,500 miles of pre-delivery journeys before the Queen took ownership.
A further 11,000 miles were clocked up before the vehicle was returned in 2004 to the Jaguar Daimler Heritage Trust with whom it is still registered.
The specially-requested modifications made to the car include a factory-adapted centre armrest that features a sliding holder specifically designed for the Queen's handbag.
The vehicle's ashtray was crafted to house the security lighting controls, which remain fully functioning. This includes a set of blue flashing strobes occupying the front fog lamp inserts, alternate flashing headlamps and alternate flashing rear lights.
The car is being sold with its original tyres, with its full-service history and with its original registration number.