I want to surrender house but ex lives abroad

Can anyone give me advice, i want to surrender a property that i have joint mortgage with my ex, he lives abroad and has no intention of returning. He put friends of his in the house and they're living there for free. He changed the locks etc when i moved out so i have no access to the house. The bank need his signature on the surrender forms but i dont think he will agree to surrender it.
Have i any rights here at all or is it just me that will be dragged through court by the bank if they repossess?

This Key Post sets out the principles involved

A guide to splitting up when in negative equity

What has changed since 2009 other than the negative equity getting a lot bigger?

Has he stopped paying the mortgage?
Has the lender been in touch with you seeking repayment?

Unfortunately, buying a house with someone who turns out to be unreliable, is a nightmare which is difficult to resolve.

Did you have a written agreement when you bought the house in the first place?

Sophia welcome to AAM.

Do you have any assets, are you in a good job, does your salary just pay for your current living arrangements and do you have children.

If you have nothing than don't worry about the bank.

Hi, yes he stopped paying the mortgage a couple years ago, i moved out on his agreement that he would continue to live there and pay the mortgage but he up and left for the other side of the world. The bank just send me monthly letters with the arrears amount on it they haven't tried to repossess yet. We didn't have any written agreement between ourselves only whatever we signed up with the bank.
I don't have any assets, i work part time, have 2 children for my ex too, im back living with my parents. Could the bank try to get money from my parents house?

Is there any legal thing in place that if i have no contact from my ex regarding the house, that i can take over responsibility and surrender the house on his behalf? I think maybe you have to be married for that but im not married to him.