The Type 45 destroyer project really began when the 8-nation NFR-90 frigate program fragmented into pieces. The USA and Canada elected not to pursue a modern frigate at all. Spain developed the 6,250t F100 AEGIS frigate, which it has now sold to Australia as the future Hobart Class. Holland and Germany developed the 5,700t F124 Sachsen/ LCF De Zeven Provincient Class air defense frigate. The UK, Italy, and France, meanwhile, embarked on the Horizon Class New Generation Common Frigate. In 1999, about 7 years after the initial requirement was floated, Britain dropped out of the NGCF project, citing a need for a larger ship, with wider air defense capabilities, and a British combat management system. Italy and France went on to order a total of 4 (2 each) 6,600t Horizon Class frigates.
Rather than using a modified variant of America’s multi-role 8,000t DDG-51 Arleigh Burke Class, whose costs and performance were stable, Britain proposed to develop its own air warfare destroyer, with better high-end anti-air capabilities. The new 7,350t base/ 7,800t full displacement ships would share the MBDA PAAMS system, built on its Aster-15 and Aster-30 missiles, instead of the popular Raytheon SM-2/SM-3 missile family. PAAMS would be complemented by a different set of radar systems on the Type 45, but the Horizon Class had different radar fittings for each country anyway.