With the new Mortgage Interest Relief Restrictions (MIRR) starting from tax year 2018 (also known as 'Clause 24'), many portfolio landlords could be seriously negatively affected, and the above question is the 'elephant in the room' - this article explains the risks involved in transferring properties into a company while maintaining underlying personal mortgages on the properties transferred.  

How beneficial to me would this be?
Clearly, the 'Holy Grail' for portfolio landlords is to be able to transfer their portfolio to a company, without needing to re-finance their personal mortgages, which may be on attractive Base Rate trackers and on high LTVs. For many portfolio landlords, the tax position is often not an issue, since the landlord would qualify for Incorporation Relief meaning that no CGT is payable on incorporation.    

Therefore, in my experience since July 2015, many landlords have wanted to properly understand why they can't simply transfer their portfolio to a company and retain their personal mortgages, since alternative options are often expensive and not hassle-free to implement.

Why can't I just transfer my personally-held properties (with personal mortgages) into my limited company?
The reason that most, if not all, landlords with personal mortgages on their rental properties can't simply transfer the properties to a company is that this would be a serious and permanent breach of their mortgage lender's terms and conditions.