thoughts:
1. under the 1925 act all leases (which includes subleases) have to be in the form of deeds (attested and in writing). On this basis, the text message wont cut it.
2. Exactly what does the text say? You need offer, acceptance and consideration for a contract. Does this contact all 3? Any lease will also need a defined term (period of occupation). Without this it will be considered to be a rolling annual contract meaning you have the right to terminate.
3. What property do have they demised to them? Just a room? Does that room have a lock? This is important as it's not considered a lease if they don't have exclusive possession. If it's just a room with no lock then the courts may consider it a licence to occupy not a lease. There is no statutory protection under a licence so you can pull the plug whenever.
There's enough to fight this I think.
UK only though!
Consent of the landlord is not required by law! But most primary leases prohibit it. The only way you will know for sure is if you ask the landlord specifically.
But the truth is that is not a problem. In real estate all contracts need to be in writing and mutually executed (signed), thus this so called texted sublet contract doesn't legally exist. That being said a "tenancy at will" does exist. This is equal to a month to month contract such that the tenant or the landlord can make any changes to the tenancy agreement with a month's notice. Thus if you want to leave you can, but will need to give the landlord a month's WRITTEN notice. If you give this notice mid month, it is applied to the first of the following month, and rent is due for that last month. Normally I would highly suggest paying that last month of rent, because not doing so allows the landlord to sue you for it. But your landlord would have a much harder time proving the tenancy even existed in court and not likely to pursue you with a texted contract. Good Luck.
A lease or sub lease doesn't have to be in writing to be valid but in this case unless the landlord has given his permission (which would mean he and the other tenant have an agreement not a you and the tenant having a sub lease). If the landlord has not given permission then both you and the other tenant have a problem because you have broken the terms of your lease and the other person has no right to be there at all.
Why would a landlord allow someone to lease their property without his/her permission? Normally lease or rental contracts prohibit the person on the lease of rental agreement from a sub leasing or renting.
Even if there is no clause in the lease agreement or rental contract you can not automatic assume that you are able to sub lease your rental unit.
You now want to know if contract you signed is valid, what was not this question important when you signed the lease that could be considered illegal.
Normally an illegal document is not enforceable. You can not take an illegal act and make it a legal act.
I hope this has been of some benefit to you, good luck.
"FIGHT ON"
Does the lease with the landlord permit subletting? Most are strictly prohibited.
Any lease has to be in writing and signed by all parties; a text message is neither considered to be in writing, or signed. So no, not valid.
Usually subleasing is illegal in a lease unless u get permission from your landlord in advance to do it
if the landlord objects to it it's illegal if he doesn't know how can he object
No.