Delisted shares and company in liquidation - when can capital loss be declared on tax return?

I hold ordinary shares in a company which has cancelled it's listing on the UK Alternative Investment Market (AIM) and gone into liquidation. The liquidator has advised an estimated amount that shareholders may receive per share but that this could likely take a number of years to realise. Furthermore, timing is also dependent on a number of uncertain factors, which have no set time period and therefore timescales could be further extended. The above means I will have a loss and I was wondering: (1) If I can declare this now based on the liquidators estimated amount per share (2) If I cannot declare it now, when can I declare it? Thanks

Hi,
The loss is declared in the tax year that the business went into liquidation.  
You would have to use the liquidator's estimate in the first instance and amend your return at a later date, to reflect the actual value.
Thank you.