When you say it hasn't done anything, do you mean it hasn't put out any leaves, or any growth of any kind? If that's the case, it might have died in its pot over the arctic winter - you haven't said where you are in the UK, so I don't know how cold it got where you are. Scrape back some of the bark with a fingernail to see if its moist and greenish underneath - if its brown and dry, it's a goner.

I think that what you mean by 'flowers' are the young leaves of the willow which are an attractive pink colour. Assuming that it is actually alive (as per bamboo's comment above) and has green leaves then it has probably been kept too dry. Salix prefer to grow in the ground and to be kept moist.