I think the top mobile makers are worried. Their sales are now being hit by good quality chinese phones. These phones offer similar performance to flagship phones and are unlocked so can be paired to a Giff Gaff card immediately. It's a no brainer really.
I'd never go with a contract again @inishtay
I had a particularly bad experience with O2 a few years ago when I purchased a text add-on which they took the money for but also charged me for the texts. I rang them and queried it and they apologised and said they would settle it next month. They didn't and the same happened the following month. When I queried it again they used the same excuse but then cut me off after two weeks as I (as their operator advised me not to, and put it in dispute) didn't pay the extra charges. They kept cutting me off for several months.
It was a nightmare - so I'll never do a phone contract again.