If my overseas apartment is vacant and I cannot find a tenant, can the empty period be calculated as a loss as no income is coming due to its being vacant at the moment? Can I count the months it has been empty and deduct the empty period rental value from the period it generated rental income? 

Arthur Weller replies:  

It is not clear what you mean in your question. But it seems to me that what you are asking is that where (for example) the usual rent is £1,000 per month, and the property is vacant for five months, whether you can deduct £5,000 from rental income that you earned during the time that the property was actually rented out (i.e. from the £7,000 actually earned), so that you only pay tax on £2,000? The answer is that you can't; the loss of £5,000 is not an actual allowable expense that can be deducted from income. It is just 'missing income'.