Can I get a loan if I have arrears on my mortgage?

YES, under certain circumstances you can.

Having arrears on your mortgage does
not always prevent you from
getting a loan. If you have arrears
when your loan completes,
all the arrears will be paid directly
by the lender from the proceeds
of your loan. So when applying,
if you want to receive a certain amount
of cash in your hand, you must add
on the amount you need to clear your arrears.