We ran into this problem we we moved to Sheffield. My partner is a student, and I was unemployed at the time, so they required a
UK resident with a stable income and good credit rating to sign as a guarantor OR we could pay for the whole lease up-front. We went with the latter, because we just did not know anyone in the UK that was able to sign as a guarantor. We were lucky in that we'd been saving up to come over anyway so we had the cash available, and there was two of us to split it, and we were able to sign a 6-month lease (even though we had plans to stay for a year). We're still in a crap boat, 7 months after - signing that original lease meant that we are not able to renew our lease on a month to month basis, but we can simply inform our letting agent 1 month in advance if we wish to stay. So we're in the process of signing another three 2-month leases to make it easier for us to pay. (My partner has a lot of liquid assets, and I'm working for a temp agency so my income is a bit tenuous at times - its easier for me to pay him back than freak out about not meeting rent every month).
You'll find the problem is not only having A job but having a job that the rental agency (or whoever) will accept as being stable as providing enough income to cover your rent and reasonable living expenses. Also, having a credit rating doesn't matter - As far as I can tell they generally don't do credit checks on your financial background abroad. Police checks (my job required a criminal records disclosure which took FOREVER because they had to write to Canada) but not credit checks.