Will iphone 4S brought in UK work in Egypt with an Egyptian Sim Card?

So my boyfriend is Egyptian and lives in Egypt for his birthday he has asked him mum to get him a new phone and he has asked me to find out the UK prices of a couple of phones and let him know as he has said to me the quality of the phones such as Iphones are better in the UK than in Egypt itself.

I have had a look online and the iphone 4S is currently around £450 from apple. This states that it is factory unlocked. My question is, if I buy this phone from Apple which is 'factory unlocked' will it then work in Egypt using an Egyptian Sim card? As I don't really want to buy the present for it not to work when we get there.

Any help will be appreciated.

Assuming Egypt works on a GSM network, it should.