Can US Virgin cell phone be unlocked for UK?

My wife is moving from the US to the UK and wants to use her current cellphone when she comes to the UK.

It is currently on a Virgin, pay monthly deal and is locked to their network.

I thought it would be straightforward to get the phone unlocked and able to be used with a UK pay monthly deal when she comes here.

Virgin USA have said that this isn't possible.

Does anyone have any experience on what we can do, short of buying a new phone which seems a bit expensive when the current one works fine for our needs.

Unlocking phones is a whole world of issues in the USA. She might have better luck getting it unlocked in the UK?

She she speak to someone directly there both in the store and on the phone. I know nothing about Virgin USA phones, but there might be something. Or I'm sure there is somewhere she could bring it to get in down, but not a regular phone shop.

another note - some US phones do have sim cards and others don't. So many she has one that doesn't. Example: iPhones with verizon don't, but with att&t they do.

When I was with Virgin Mobile, my phone didn't have a SIM card. 

Earlier this year, we tried using my wife's US pre-paid Virgin iPhone. It simply would not work. Took it to a UK Virgin store - they tried adding sims to no avail and gave up after trying several methods spanning an hour.
We ended up buying a cheap, non-contract phone to use.
I did call VirginUSA and they confirmed that the no-contract phones will not work in the UK. Kind of ironic if you ask me.

However, according to VirginUSA's website - they will unlock their phones under a new policy starting in Feb 2015 if you can wait.
newcomer link: http://virginmobileusa.custhelp.com/app/answers/detail/a_id/5815 [nonactive]

I am a prepaid customer. Am I eligible to have my device unlocked?

Neither Sprint nor its prepaid affiliates (Virgin Mobile, Boost Mobile, and Assurance Wireless) currently unlock devices for prepaid customers. However, in accordance with the Unlocking Commitment, Sprint and its prepaid affiliates are working to create new policies and procedures in order to unlock prepaid devices, or to provide the information necessary to unlock the devices, after certain eligibility requirements to be established are met. Consistent with the Unlocking Commitment, Sprint and its prepaid affiliates will implement these new policies and procedures no later than February 11, 2015.