Six of the vehicles carry full MoD police livery and are primarily used to oversee a number of defence estate sites and military bases.
The other six cars will remain unmarked, allowing the MoD police to use them for criminal investigation work, as well as other administrative operations.
Andy Bryant, fleet manager for the MoD police, based near Braintree in Essex, said: 'We wanted a car which was compact but could offer spacious and flexible passenger and load carrying capability. It also had to be fitted with an economical diesel engine and with a good turn of speed when needed.
'Having surveyed the market closely, the Mitsubishi Space Star met our specification criteria in full and was the most competitively priced car in its class. We have had our new fleet in service for a number of weeks now and are already pleased with how well these cars have performed.'
The MoD police has favoured Mitsubishi cars in the past, purchasing two 3.2 D-ID LWB Shoguns last year for special assignments. It has just placed an order for four more.