Unless your parents can provide for your monthly expenses till you have graduated and have found a professional job, you require a part time job to survive abroad.
Finding a part time job is a challenge in itself. Finding a job that you can adjust to is another.
In UK, no job is considered menial. Whether you are a bus driver, whether you are a waiter/waitress, whether you are on the streets distributing leaflets - you are treated equal.
Unfortunately, most of the students do not have the above mentality.
Your life will become easy and less disappointing if you are ready to adapt yourself and can commit to such part time jobs. After all it is only going to be a temporary job.
Being on a student visa, I was allowed to work 20 hours a week. I found my first part time job through a friend of mine. It was at a dog race stadium where my job was to issue race tickets. I worked 3 days a week for 10-12 hours. The income was just enough for me to manage my expenses.
While working at the dog race stadium I started looking out for other part time jobs as I needed a boost to my income. Within couple of months I got a job at a call center. I started working 20 hours a week. I attended my university classes in the mornings and worked at the call center from 18:00 - 22:00. I learnt to balance my studies, job and house hold chores. Of course, it was not easy.
After a year, I found a part-time job at the British Telecom call center near where I lived. This helped me save my travel time and offered a better income.
While few students manage to work at the call centers and earn admin jobs, there are few students who have tough jobs. For example jobs like, selling international calling cards on the streets in freezing cold, working night shifts at petrol stations, super markets, working at Mac Donald/KFC where students are expected to clean the customer toilets.
Although you should try your best to earn a good part-time job, at the same time you should not be disappointed if you cannot earn one. What matters the most is that you remain focused on your ultimate goal and earn money the right way.