Small mortgage increase aplication, or loan?

Thinking of moving house. current house valued to sell quickly at 240k. asking price of house we are loking at is 295k but is way over-priced and I have a feeling it might go for 260k.
We will be transferring 80k of negative equity with our current mortgage.
If we apply for a brand new mortgage, we will have to come up with a deposit.
The deposit would probably be approx the same as the difference in value between the 2 houses, ie 20k.
Would i be just better off getting a short term loan to make up the shortfall and just transfer over the mortgage to the new property?
pros and cons, opinions?
Thanks.

What do you mean transfer over the current loan to the new property, you cannot do this.

You sell for 240K with NE of 80K. And you propose buying for 260K (or thereabouts) with the NE of 80K makes a loan of 340K.

Can you afford 340K? You don't even seem to have a deposit and want to borrow it so that would seem to indicate you don't save and ergo you cannot afford a 340K mortgage and loan?

Current mortgage 320
Sale price 240
NE 80

New property 260
NE 80

Are you sure your bank will allow you to transfer negative equity?

Also, you'll have to get a new mortgage as your current mortgage is tied to your current house and cannot be transferred.