When was a retention payment earned?

The taxpayer was non-resident for 2013-14 returned to the UK in 2014-15 and was UK resident for 2015-16. He was employed by B when in October 2013 the company announced it was to be acquired by PwC. On 17 December 2013 B announced that eligible employees would qualify for a payment from a $50m retention pool. To qualify they had to be an ‘active permanent employee of B in good standing’ on 31 December 2013. Payments were made on 28 April 2015 and the taxpayer received a $30 000 retention payment on that date.

The taxpayer said the payment was for ‘continued active employment in good standing’ as part of a retention strategy. He earned it during the period from 1 January 2014 to 28 April 2015; so the payment was ‘for’ those 15 months. It should be apportioned over the three years covered by that period on a...