Last time I read the regulations, I was given the impression that as long as its a reflected light (i.e. you cant see the bulb directly) and its not flashing, then any colour is allowed if its being reflected forwards or sideways.
There are strict limitations on what is allowed pointing in a rear facing direction.
I doubt however a judge would side with a rider with blue lights though - even the 'chavved up wipers' are no doubt fine inducing if you get a cop on a bad day....
The short answer is no.
In relation to your bike and 99% of vehicles used front obligatory and optional lamps are required to be white.
In relation to colour, the only colour specifically having it's own offence is showing a RED light to the front. The offence for other colours is combined.
In relation to blue lights, if they are flashing, or can be switched on or off ie. flashed, then they are resembling a warning beacon or special warning lamp which is a separate offence.
LAst time I checked with the Home Office and DfT, as part of a study, they confirmed that blue lights, whether working or not (and including to pushbikes!), may not be fitted to a vehicle full stop. The precis edefinition of clue is given in the usual chromatographic fashion.
Flashing lights other than amber are not allowed on powered vehicles in any case.