If your mortgage payments go down, you should inform your IP and it is possible that your payments will go up.
Similarly, if your mortgage goes up, then your payments should reduce.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
It depends on the scale & how much the difference is.
Jan is right, you should inform your IP. Though I generally only informed mine of flucuations at the annual review stage & was never questioned about it!
Mine only alters once a year, fortunately that is just before my annual review!
If it did, then I would contact the IP just to inform them - the rest is up to them.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
To be on the safe side I would let your IP know when the change happens rather than waiting until the annual review. At least you'll have no nasty surprises at annual review time!
You can definately expect your payments to be adjusted if your mortgage rate reduces, but this may also be an opportunity to revisit other areas of your expenditure to see if you are adequately provided for.
And do remember that mortgage rates may also rise in the future so your payments may well have to be adjusted back at some time in the future.