Your tenancy agreement gives you the legal right to buy your home if:

You can buy your home at a discount price below its market value - the longer you have been a tenant, the bigger the discount. If you live in a house you will get between 32 percent and 60 percent off the market value. The discount if you live in a flat is between 44 percent and 70 percent. But the discount can only go up to £26.000.
Although Northwards Housing manages your home, you would be buying it from the City Council who still own it.
If you buy your home, you can sell it in the future - but if you do this within a specific time you will have to pay back some or all the discount. If you applied to buy your home before 18 January 2005 the specific time is three years. If you applied to buy your home on or after that date, the specific time is five years.