Agree with the complete twaddle comment. The FSA wouldn't allow it for a start.
Also, as for the person that said if its to cover a mortgage you need DTA, not strictly true, it's clearly dependent on the mortgage that they take out, so if they take an interest only mortgage and then get a DTA on your advice, they'd be pretty screwed in the event of death.
As for this question I would always say if you have little to no idea it's always best to speak to an IFA as they take into account all of your personal circumstances, especially the fact that you have a very young child as well.
For instance if you were to take cover for the mortgage purely, there's no thought given to what age your daughter may be and what stage of life, for instance the survivor may need to come out of work to look after her etc, or university fees.
There's generally several connotations to think of before coming to a decision on figures needed to cover.
Hope this helps :)