The losses need to have arisen as a consequence of the unfair dismissal, as a result of your employer’s action.
The main heads of losses that you can claim are:
loss of wages;
loss of future wages;
loss of statutory rights (it takes 2 years before you have unfair dismissal protection, or you can qualify for a redundancy payment);
loss of pension.
The maximum amount that you can be awarded as compensation for Unfair Dismissal is presently the statutory cap of £78,335, or 52 weeks gross salary whichever is the lower. This is in addition to the basic award which can be ordered by the Tribunal of up to a maximum of £14,250. These figures are correct as at 2015.
In some cases, there is no cap on the compensation that can be awarded. These include cases of discimination and whistleblowing. Unfair Dismissal is a vast area and each case is determined on its facts. You should obtain professional advice as soon as possible if you think you have a claim.