http://www.ukba.homeoffice.gov.uk/vi...ionship-ended/

Partners of British citizens and people who are settled here

If your relationship ends while you have temporary permission to stay in the UK - that is, during your two-year probationary period before you can apply to live here permanently - you should tell us about the change in your circumstances and whether you intend to leave the UK. Since you no longer meet the requirements of the Immigration Rules under which you were given permission to stay here, we may consider whether that permission should be cancelled.
If you are a British citizen or settled here and your relationship with your partner ends during their probationary period, you should tell us that the relationship has ended. Our Partners and families section contains more information.

http://www.ukba.homeoffice.gov.uk/vi...tionship-ends/

This page explains what to do if you are a British citizen or a person settled in the UK and you end your relationship with someone currently who has permission to enter or remain here as your partner.

If your marriage, civil partnership or other relationship permanently breaks down while your partner still has only limited permission to stay in the UK (that is, during the 2 or 5 year probationary period before they can apply to live here permanently), you should tell us by writing

In this situation, we may curtail (cancel) your former partner's permission to stay in the UK. However, this will not automatically happen if the basis of their stay has changed - for example, they may qualify for permission to stay on a different basis, or there may be other compassionate or relevant reasons why it would not be appropriate to curtail their stay.


So it seems that they may not be sent home and would be given permission on a different basis and therefore may be able to claim benifits?