Is there any bias among employers towards foreigners?

I'm in the UK for more than five years already, I initially came for undergrad study and now finishing my Masters in Marketing. While studying I found a job in gaming (my favourite thing) as a community manager and worked closely with marketing guys, so my choice of Masters was obvious. Now I want to move to a bigger gaming company (which are plentiful in UK) as an intern, junior employee or maybe even a proper position in marketing. I've done many things at work and learned a lot from Uni so I am not really worried about my career as I'm sure I'll land a decent job. While I have this confidence, I never thought about certain disadvantages of being a foreigner before my mother told me recently that employers would rather hire locals than me. I am from Eastern Europe (Estonia) and I can speak two and half languages and have this working experience + education, but now I became worried that it may be true what my mother said. Of course, it is not going to stop me from applying for jobs, but I am still slightly concerned that a company would rather hire a lower skilled local guy than me purely due to whatever reasons they may have based on my origin. If there is anyone here who experienced this at work? By the way, I have almost never had any problems at my current job or with people outside.