Banking a loss

My client acquired a property in the USA in 2004 and with the agreement of the mortgagor has sold it recently at a loss of about US$480 000.

At the exchange rates applicable to 2004 and 2010 this equates to a sterling loss of about £200 000. The rental income during the period of ownership has been declared to HMRC although there has been a loss every year.

The mortgagor a US bank has agreed to waive repayment of the mortgage balance at sale (about £160 000).

My client has been advised that the loan waiver will need to be declared to the US tax authorities and there may be US tax consequences. The US tax agent will deal with these matters.

I need to confirm whether or not there are any UK tax consequences for the loan waiver and...