girlfriend wants half!

[tecplumbing]

bit of back ground:-

me and the now ex have been together 7 years, lived with at hers for 5 years before i brought a house in may and then she moved in. was all my deposit, mortgage is in my name, shes just been paying the electric and virgin bill.
3 months later and she tells me shes leaving, trying to be civil but shes turned nasty and telling me shes entitled to half.
where do i stand?

[tecplumbing]

no kids....
not on the mortgage and has not put any money in to it.
she wants half the house. and has just told me shes not paying the bills now.
was reasonable at first. told her as we had history ect i would give her time to find somwhere else.

[tecplumbing]

the tv package/ water/electric/ insurance...since start of may

[tecplumbing]

thought so. she hasnt actually paid the electric. just gave me a bill for 300 and said shes not paying it.

[tecplumbing]

just told her i will deal with her solicitor and end of. told her she now has 2 weeks to leave.