Paying off mortgage on rented property with a lump sum? Or not?

Slug_62

I have a £135K interest-only mortgage outstanding on a property I own (accidental landlord). Took it out 2018, due for renewal in December. Currently paid £250 per month, get rent, after agency fees, of £850. My mortgage broker says I will be paying around £550 with the new increases when I renew in December.
I came into a windfall of £155K and I don't know whether to pay off the £135K mortgage or invest the £155K. My mortgage broker says pay off the mortgage, my accountant says keep the mortgage and the lump sum, as does my brother, who is a successful businessman. 
Any ideas of what best to do? I know I am in a fortunate position but I have never been in this position before and would really seek views

BikingBud

Why do the people that know you, and your business, offer different advice?

Have you asked each of them how their proposed course of action will benefit you? Ask them to show you the figures.

How do they match with your expectations and aims in the short, medium and long term?

Do you understand all the potential benefits and pitfalls? You say "accidental landlord" but these are important decisions that you must make. If it really is accidental then warn the tenants off , sell off take the equity and the windfall and move on.

Failing that ask a bloke down the pub who says put it all on black you cannot lose!

dimbo61

Like many thousands of Landlords all over the country your facing a Massive increase in your mortgage costs without being able to Increase your rent by £300 a month.
Tax changes S24 make it even worse.
Now if your clever like your brother you might turn the £155K into a handsome  profit by buying shares in The Hut Group or any one of a hundred companies who have lost money this year.
Or you could clear the mortgage and have a steady income ( same amount as your state pension each month ) 
Are you paying into a company pension ?
Do you have an ISA ?
Do you have residential mortgage  debt 

silvercar

All depends what else the £155k could give you. Further investments or savings etc compared to the cost of the mortgage, allowing for it to be expensed at basic rate tax level only.