To answer this question lets understand what the Enclosure Acts were about. Those laws intended to create a legal status of the property to lands that were often used as common land. As a result, peasantry and rural laborers that have been using those lands for generations were left with no land or having only a land of low quality as compensation.
The peasantry had no many options to choose. and one of them was to migrate to already crowded cities to find a job. The Enclosure can be seen as early as the 12th century but it climax ranged from 1750 to 1869, coinciding with the emergence and rise of the Industrial Revolution.
Establishing those two events together we can see the increase of urban migration as a result of the Enclosure Acts and the raising demand of workforce created from the Industrial Revolution.
