The devolution instigated in the United Kingdom in 1997 was a further stage in a long historical process. Nonetheless, prior to the 1990s, the basic structures of career guidance services were broadly similar across the UK. But the marketisation of careers services that took place under the Conservative government in the mid-1990s went further in England than elsewhere. This helped to pave the way for the markedly different directions followed post-devolution, with England seeking horizontal integration of services for young people and adults respectively, whereas Scotland, Wales and Northern Ireland have emphasised vertical integration of career guidance services on an all-age basis. Some sectors have been affected less by devolution than others. It is suggested that the model adopted in England has already weakened the structures for career guidance provision, and is currently at risk of weakening them still further. The relative size of England means that these weaknesses could have ripple effects on the other home countries too--in relation to professional training and professional status, for example. Existing collaborative mechanisms need to be strengthened, and a culture of mutual learning enhanced, if the potential benefits of diversification are to be fostered and its potential risks avoided.