Standard Variable Rate
Your payments move up or down with the lender's own mortgage rate, which is usually driven by the Bank of England's base rate.
Usually you can leave your lender without any penalties or problems.
You're in control. You can usually pay back extra amounts (and cut your interest costs) without a penalty.
It moves with interest rates. So if interest rates go up, so will your monthly payment.
It will almost certainly be expensive compared to other deals.
The lender may not reduce, or may delay reducing, their variable rate even if the Bank of England rate goes down