In terms of industrialisation, Scotland was a late starter compared to England. However, from 1830, the country experienced a massive surge in the expansion of an interlocking economy based on heavy industry - that is coal, iron, engineering and shipbuilding.
In a very short space of time, Scotland became more industrialised than the rest of Britain; indeed, it became the workshop of the world. The main ingredients in the creation of this powerhouse economy were cheap and plentiful supplies of raw materials and energy, a vast reservoir of low cost but reasonably well-educated labour, entrepreneurial dynamism and a university system that developed close links with industry.
Rapid industrial growth led to the mass migration of labour to the cities in search of work and accommodation. Such a movement of peoples saw Scotland rise from fourth place in the world urban league in 1800, to second only to England and Wales by 1850. However, the unplanned growth of the cities and towns created squalor and over-crowding on a massive scale.
Even as late as 1911, two-thirds of Scots were living in one- or two-roomed houses compared with only 7% in England. Poverty was widespread, wages were low in comparison with other parts of the UK and infant mortality rates were alarmingly high.
Furthermore, these social problems in a pre-welfare society were intensified in times of economic depression. Scotland's economy was based on exports, mainly to the British Empire, thus, boom and bust were core elements in the economic story of its development.
This culminated in the late 1920s and early 1930s in a catastrophic economic collapse which saw around a quarter of the working population of the west of Scotland unemployed. One of the ways out of the economic and social problems in which many Scots found themselves trapped was migration.