Is it dangerous to leave a washing machine plugged in and switched on continually ie overnight or for any length of time when not in use?

Yes, leaving a washing machine plugged in and switched on for extended periods, such as overnight, can be dangerous. It poses a risk of electrical fires, especially if the machine has a malfunction. Additionally, continuous power can lead to wear on the machine's components. It's safer to unplug the appliance when not in use.