Way back in the 1980s, the Ministry of Defence was trying to turn the Hawker Siddeley Nimrod into an Airborne Eartly Warning aircraft. After spending hundreds of millions of pounds trying to get the new radars to work, the project was cancelled and the government bought the Boeing E3 Sentry instead. However, the MoD apparently didn't learn the lesson. When the Nimrod MR2 became due for replacement in the 1990s, the Nimrod MRA4 programme was launched. This was to be a total rebuild of the MR2, with new engines, new wings and new avionics. However, fitting new wings to 50 year-old hand-built fuselages proved to be a problem. After spending many millions of pounds on the project, the government cancelled the MRA4 programme in 2010. However, this has left a bit gap in our Maritime Patrol capability. With Russian submarines carrying out incursions into British waters, something is needed to fill the gap. That something comes from the same source as the E3 Sentry; Boeing. The P8 Poseidon is designed to replace the ageing Lockheed P3 Orion. Poseidon is a brand new aircraft, based on the design of the popular 737 airliner. It will me much cheaper than MRA4, which begs the question, why did the government not purchase it in the first place, instead of wasting all that time on the MRA4? Probably because the P8 wasn't even in planning when MRA4 was proposed. Yes, the MRA4 was in development for so long that the P8 has gone from nothing to in service with the USA in less time than it took for BAe to rebuild the Nimrod.