2 years ago our solicitor advised us to stop paying our mortgage to a Spanish bank. The bank had given us a mortgage on an illegal build in 2006 (not that we knew this when we bought it). We moved back to the UK and continued paying the mortgage for 4 and a half years in the vain hope that it would be legalised and sold with a clear conscience. As costs of living had risen in the UK, we were struggling with repaying the mortgage and renegotiated with the bank and moved to an interest only mortgage for a year. We found this impossible too especially with no legal resolution in sight and so we contacted a UK/Spanish firm to manage our extraction from the mortgage. The keys were sent to Spain over a year and a half ago to the law firm but the bank valuation was only completed this year in June and the bank has decided that we are in negative equity by 20,000 euros. So will not accept dacion en pago, but will give a personal loan for this amount which we cannot service. We rent in the UK, have no assets and are in debt here. Our solicitors have advised us to accept the offer by the bank but has the solicitor been negligent in its advice to us? Also, did the bank fail in it's duty of care to us by granting us a mortgage in the first place and not advising us that the property was illegal?