The BLR wheeled APC was developed to meet Spanish Army requirements for a low cost protected cross country vehicle which could meet various border patrol, internal security and airport security functions. The BLR was developed by the Santa Barbara Group and was designated the BLR 3545.

The layout of the 4 x 4 BLR differs from most other vehicles of its type in having the engine located ventrally at the rear, over the rear axle. Once the occupants have entered via two doors in the hull rear (there are also two side doors, one each side) the interior therefore has a relatively large unimpeded area with space for 12 occupants plus the driver. Vision blocks are situated along each side wall while the vehicle commander is provided with a centrally-located cupola featuring all-round vision devices. If required, a 7.62 or 12.7-mm MG may be mounted over this cupola, possibly in a small turret; it has been proposed that this weapon station could accommodate heavier weapons, such as 20 or 25-mm cannon or even a 90-mm gun turret, but non has been installed.

Special equipment provided for the internal security role includes a barricade-clearing device or dozer blade, sirens, loudspeakers, spotlights and smoke or CS agent dischargers. There is also an unusual semi-automatic system located over each wheel station to extinguish fires. Other optional equipment includes extra radios, run-flat tyres, a front-mounted winch, and night vision devices.

The Spanish Marines operate the BLR while more are employed by various Spanish police and para-military forces operating in rural areas. Export sales have been made to Ecuador.

Although no BLR variants have been produced to date it has been proposed that the usual command and ambulance models could be readily produced. Production of the BLR has now ceased.