Adding a joint tenant...

[hocus103]

I have been renting a bedsit with a housing trust for 3 years. The bedsits are suitable for only 1 person (under the housing trust rules.)
I met my boyfriend, and he has been living with me for almost a year in the bedsit. It was cosy at first but now we need that extra space!
The only way I can transfer to a one bed flat with the trust, is if my boyfriend becomes a tenant and, I am then classed as overcrowded.
My tenancy agreement states that in order for some one to become a joint tenant, they have to have been living with you for a year, and have
bills in their name to prove they are living there. But, they ‘still have the right to refuse.’ That’s no problem as all his bills come to my address.
But, I had a brief conversation with the on-site Manager at my estate, who told me that they probably WON’T let me add a joint tenant precisely because they will then HAVE to move me to bigger property as I will be a priority due to being overcrowded. But I AM overcrowded. Before I start pursuing this, and send my application through, I wanted to find out if any one knows a bit about joint tenancy, and if I stand chance. Surely if I can’t add my boyfriend to the agreement, they have to have a valid reason for refusing me? So frustrating - but I haven't officially been refused, its just this one Housing Trust worker, who made the unofficial comment....