You don't need to go Bankrupt here or in England . Tell the person who is going to will you a site to will it to your kids instead .Only problem I can see is if you rent another house after surrendering your home you may have to pay the rent yourself for 6 months so you then qualify to apply for rent supplement . Maybe someone else knows more about this.
When the bank gets a judgment against you in court for the balance between the amount they sell the property for and the outstanding owed on your mortgage, the bank will then have a few avenues open to them to recover the judgment amount, more than likely they will ask for your income ,assets etc to be assessed by a judge , but from what you say you have no wealth/assets and an income from social welfare only so the judge will tell the bank tough luck !
The judgment will sit on your name for 12 years accruing 8% interest per year , if in that time the bank becomes aware you have won the lotto, inherited a house/land/money
got a well paying job etc. etc.
they may try get you reassessed by a judge to get their money back .
The judgment becomes void after 12 years from the original judgment date and you are free from it at that stage.