Can i pay for a Iphone 5 in monthly installments?

My son is on Tesco mobile and he don't want to change my contract so hes getting an Iphone 5 on Pay As You Go, this means paying out £529 in one lump but there's the problem, i've got £350 and need another £230 but i won't have it until christmas so is there a way that i can pay for the iphone in monthly installments because i need the phone there on christmas day for my son.

can any one help?

Some shops may do this, but not all; you need to ask. But I think you should consider whether your son Really needs this phone. You clearly can't afford it, and no person in the entire world has ever died from iPhone withdrawal. If your son is old enough to get a job he should do that and buy the phone himself- and if he's not old enough, then he's also not old enough to be responsible for an expensive phone.

Use a credit card and pay it off as fast as you can. There will be interest but that's the only way I can think of that's possible.