There is certainly a rise in the visibility of neo-facist groups and, in some ways, further-right-wing political views are being expressed more openly.
Significant power, no. In the UK there is less than 70 days until the general election meaning that ALL seats in parliament will be included in the vote so there is the potential for a huge change in the composition of the parliament.
In recent times it's been more or less a straight choice between a Labour or Conservative majority government (very slightly left v a bit more right) with small numbers of members from other parties but in the last election neither party attained a majority leading to the current coalition (Conservative & Liberal) that we have. This time around, if polls are to be believed, there will be a large number of MPs coming from minor parties, especially the SNP and UKIP either of which may be in a position where they hold enough votes to be able to form another coalition with one of the major parties.
In this situation, where there is more deviation from the centrist norm, I could see a far-right-wing party gaining a voice, but not power, in parliament. I don't think it will happen this time around but it is a possibility in the further future. UKIP are, in some ways, the furthest right party that we have so I suspect that much will depend on their results and, assuming that they get a significant number of members into parliament, how they perform over the next 4-5 years.
It doesn't concern me much at the moment. In fact, I think that having a broader range of interests represented in parliament may well be a good thing. I certainly welcome the presence of dissenting voices willing to speak against the established more-or-less two party system.
