Should I accept a Permitted Occupier?

I have never dealt with such a situation, my first thought is I would say no,. If I considered such, I would make clear that the main tenant is still liable. It feels a bit scam situation / bait and switch. I cannot think of a good reason to agree.

Permitted occupiers are simply guests. They don’t gain tenancy rights and normally if the tenant left you could just exclude them and change the locks. However:
1. Being the spouse of the tenant may give them some rights under family law – you’d need to check
2. If they contribute to the rent, they could become a tenant.
3. Your insurance or mortgage may require all adults to be named tenants

Only time I have come across this is when a tenants son moved in for a few months. I agreed to it and he has since left. I had my estate agent draw up a letter that he was a permitted occupier. As far as I know they have no right to occupy the property once the person on the lease leaves, but in today’s world who knows.

https://www.hiscox.co.uk/landlords-blog/permitted-occupier-guide

The only legal thing you have to deal with is Right To Rent

Weigh the following pros and cons before deciding:
Key Advantages
Strict Control: Permitted occupiers live at the property but do not have tenancy rights. You can legally remove them without needing their permission if the arrangement ends.
No Financial Privity: Because they are not on the lease, they have no legal right to stay if the primary tenant moves out.
Simplicity: It provides a straightforward way for a partner, caregiver, or roommate to reside in the unit without renegotiating the entire primary lease.
Major Risks No Rent Guarantee: You cannot legally demand rent from a permitted occupier if the primary tenant fails to pay.Occupier
Liability: Under the Occupiers’ Liability Act, any legal occupier or person in control of a premises shares a duty of care to ensure the property is safe for visitors and guests. This can complicate insurance or liability claims in the event of an injury.
Eviction Complications: If the relationship between the primary tenant and the permitted occupier sours, the permitted occupier may refuse to leave, causing disputes that the primary tenant will have to manage.

The other thing to be aware of is that since the abolition of s21, there’s nothing you can really do about it if you say no and they ignore you.

Thank you all for your comments, very much appreciated. My gut feeling was not to do it as I have never come across this in 20 years of being a landlord and with the rental market being what it is now who knows what could happen. I am being put under a lot of pressure by the tenant to allow it, which seems strange in itself when I have offered a new contract including her husband. Why she did not want him on there 4 months ago is a bid of a riddle in itself, unless he does not want to be referenced.

Reply to the comment left by Karen at 10:06
Perhaps its a reconciliation that she is not sure will work and doesnt want to risk losing her home if it doesnt. Seems like a reasonable request to me and there are disadvantages for the landlord to creating a new tenancy, such as re-starting the clock on key eviction grounds and rent increases.