UK Landlord Forum / Life

I am a tenant in a HMO. I found a new house to move to several weeks ago, and agreed a move in date with the new Landlord. But my current letting agency would not let me hand my notice in on my current house (or give me a reference despite being a good tenant for many years) until I found someone to replace me (which took quite a few weeks as first person I found dropped out last minute).
I found someone else to take my place and they were going through referencing with the agency, and I was just about to give my 1 month notice this week.
However before I could do this, the letting agent told us the landlord is now serving us with a section 21 notice to quit- so a) the new tenant has been told they cannot move in and because there is no one to replace me,  b) the agent has told me I am now committed to stay and pay rent for the whole 2 months of notice (becuase there is no one to take my place)- with is of course making it hard for me to be able to move to the new house as I don't want (and cannot afford)  to be paying 2 lots of rent at the same time- basically originally I wanted to move by early April, but was committed to leave 1st of May when new tenant would have taken my place- but now they cannot move in due to the section 21, it seems I am forced to stay till beginning of June- is this legal or fair? (well obviously it's not fair- but is there anything I can do?)

Are you actually (still) in a fixed term contract?