Tax Implications for Subletting a Room in a Rented Flat

If I am renting a flat from an agency and have sublet a room to a friend who pays half of the rent and bills to me. She transfers this amount to my bank account, covering what I’ve already paid to the agency. I don’t make any profit from this arrangement. Do I need to pay tax on the money she sends to my bank account for rents? An accountant mentioned that I don’t need to file a tax return if the subtenant is added as a permitted occupier. Now, I would like to seek your opinion on two different situations: 1. If the subtenant is officially added to the contract as a ‘permitted occupier’ but without the role of being the tenant responsible for rent. 2. If, for a duration, the subtenant was not officially added as a permitted occupier due to systemic error, even though the agency was informed of her presence, what are the tax implications in these scenarios? Thank you.

Hi

Please have a look a the rent a room scheme:  Rent a room in your home
If your income from renting the room is below £7500 per year, it is not taxable and does not need to be declared and you do not need to complete a tax return. 
If you exceed £7500.00, you will need to declare on a self assessment tax return.

Thank you
 

Thanks for your response. Just before I received your reply, I called HMRC. Your colleague, I believe, understood my question better as it was explained over the phone. They informed me that since I'm NOT earning any money or profit from this rent, and I'm simply transferring it from my account to the agency's account, this money is not liable for tax and I do not have to declare it. This makes sense. As I mentioned, I am not earning any income from this transfers. The only issue is that I am acting as the intermediary between a tenant and the agency. Thank you for you attention to this matter and I would appreciate your confirmation.