"I think you would be far better off setting up a flexible savings account and using that as a home for the savings you are making as a result of ridiculously low interest rates on your mortgage. That way, if your financial situation deteriorates, you will still have control of your cash and will be able to maintain your life and your credit rating whilst you seek a longer term solution eg a new job.
In an ideal world you would try and convert your mortgage to an off-set: I have, and rather than paying lumps off the capital and lose control of my cash I retain full control of my cash whilst still building up a pot of money for eventual repayment of my mortgage if things go well for me."
