It seems that I (and Robinia) are not right
"Debts
Living together and marriage
You are liable for any debts which are in your own name only, but not for any debts which are just in your partner's name.
You may be responsible for the whole of debts in joint names and for other debts for which you have 'joint and several' legal responsibility. For example, in England and Wales, if you owe council tax, you and your partner will both be responsible for the debt, regardless of whether one of you contributes or not.
If your partner has a debt for which you have acted as guarantor, you will also be held legally responsible for paying it.
If you're married, you will not be responsible for any financial obligations or debts that your partner had before you were married."
For more information, in England and Wales, about joint debts if you split up with your partner and aren't married, see Breaking Up Checklist on the Advicenow website at: www.advicenow.org.uk."
Got the above from this website.
http://www.adviceguid...legal_differences.htm