I spent 2 summers with 2 friends when I was 13 & 14 picking raspberries at a local farm, We walked there (2 miles each way) for 6.30 am because we got a premium rate of 4d a pound before 8.30 so that the prime berries could get to market that day, then a quick breakfast and picking berries for jam at 3p a pound until 12ish. We managed to make a decent amount, cash in hand of course, but had to fight off lots of what would now be called sexual harassment from the farmer's sons who were the supervisors.
Later when I was working in town, I used to see the busses hired by farmers to take people to the berry fields and later in the season to the 'tattie howking'. That came to an abrupt end around 1968 when the busses were stopped by the DHSS + police and many of the berrypickers were fined and or had their benefits stopped for fraudulently working 'cash in hand'. In those days the rate of unemployment benefit rose considerably after 6 months, so to declare short term casual employment meant a huge drop in income for the following 6 months. Although the owners of the berry fields were not charged with breaking employment laws, the loss of this ready supply of casual labour led them to stop growing crops which had to be hand picked. A few tried to continue on a 'pick your own fruit' basis but that soon fizzled out as it was not profitable.