The Rolls-Royce RZ2 poweredBlue Streak, the British MRBM and the Europa space launcher for ELDO.
The RZ2 was a development of the RZ1 that was basically a copy of the North American S3 motor for the Thor IRBM.
The RZ2 was an indigenous design by Rolls-Royce, but based on the RZ1/S3. A pair of RZ2s was fitted to the Blue Streak and each installation was ground tested at the Spadeadam test facility in Cumbria. Flight tests were carried out at the Woomera range in Australia.
The example in the photo is on display at the Museum of Flight at East Fortune.