The original lessee may do so if that lease does not cause damage to the original lessor of the dwelling. Before you move as a subtenant you must ensure that the original tenant has the right to take you as a subtenant. You are also considered a sub-tenant if you live in part of the dwelling and the owner of the dwelling lives in the same dwelling. And you do not need a lawyer

Hey

I used to have a rental arbitrage business where we were managing 75 units (mixed use for AirBnB and Co0Living) in the UK.

I would prepare for this eventuality upfront and speak with a lawyer to draft a template rental arbitrage lease for you to make sure that it's watertight and largely in your favour as the tenant.

Once you have this template document, you present it to the landlord as part of the offer that you put forward and explain that you have a standard set of terms for all of your rentals to enable a uniform management process for all of your properties.

The landlord may come back with amendments and then you enter a negotiation stage where you have deal points that you are prepared to accept, those where you are prepared to compromise and those which are deal breakers and you're not prepared to accept.

If you don't have a standard document that you use, you can spend a lot of time, effort and money on lawyers fees having to review different leases from different landlords, which is not cost or time effective.

Hope that helps and if you want a deeper dive to go through some specific points I'd be happy to jump on a call.

Good Luck!