If parties are in a qualifying relationship and have not signed any properly executed agreements under the Property (Relationships) Act 1976 detailing the status and ownership of their assets, they will be governed by the rules set out in that Act, including equal division of relationship property.
There are also, possibilities for the sharing of increases in separate property that have occurred during the relationship, along with perhaps adjustment/compensation where the living standards and income of one party is significantly higher than the other as the result of the way each party's roles were divided during the relationship.
There may also be issues of spousal maintenance where one party cannot meet their reasonable needs and it is reasonable to expect the other party to contribute to the shortfall (and they are in a position to do so).