It will depend on the landlord. Granted, I'm in Scotland, but I think that's probably the case everywhere. What I had to show my landlord was my EU passport (showing I was eligible to live in-country - you'd probably send a copy of your visa, if not EU or dual UK) and proof of income. I also gave them a letter from my then-current landlord, but they said it wasn't needed. I had spotted the flat on the Rightmove website before moving over, so I'd contacted them while still in the States. They accepted an application from me in advance, with the understanding that nothing was binding until I saw the flat and wanted to move in. The flat had been refurbished a couple of months earlier and was vacant - probably because the rent was a bit too high for the area. (Other flats went for cheaper as they came vacant after we moved in.)
They allowed me to put my deposit and my first month's rent on my credit card when I arrived and we signed the lease, as they knew I didn't have a UK bank account and wouldn't until I got the letters from the Utilities and Council Tax to show the bank I was living here. I had pre-booked viewings at a half-dozen different places prior to arriving, and saw our current home on the second day of viewings. Love at first sight, this place was.
