Probably by whatever he likes, though he would be stupid to put it up too much and risk having to find a new tennant if you coldn;t afford it. He must give you adequate notice however, so odn't be bullied into an immediate increase. If you have to give him a month's notice of vacation, he'll have to give you the same for any increase.
can only offer u a guidance of what my landlord does. they increase it by 5% each april the 1st.
So if u are paying �400 at the moment u would expect it to be about �420 when it changes. But like i said, that is only what mine do and not a standard
I moved here 2 years ago and paid �400 pm until this month. It's now �450 which might seem like a big increase but most other privately rented houses round here (not as nice as mine) are around �600 pm so I'm not complaining. I've got a fantastic landlord who never bothers me and even forgot to renew my lease last year because he'd forgotten about me. 'You always pay on time and we never hear from you'! If I have a prob (twice) he's been here next day to sort it.