Negative Eqity Mortgage .. but wanting to move.

Hi Guys,
I am currently in negative equity on my mortgage .. at a guess by around £15k - £20k. I am wanting to move home. Does anyone know if the following is possible .. To make a house purchase on a much lower house value, and take add the 'negative equity' onto a new mortgage on a new house ? ? Or do I have to wait for another 10 - 20 years to get out of the negative equity ? What are my options ?

Thanks in advance.