Share options

[Brightonian]

I am preparing a tax return for someone who was US resident when options were granted in 2011. He returned to the UK and was UK resident in 2014, when the options vested and he sold the shares. He worked for the same company throughout. They time-apportioned the gain with part being taxed under PAYE and part taxed in the US.
I have looked at the relevant HMRC manuals but am unsure how to treat the US portion on his 2014 UK return. Do I just exclude the US portion completely or do I include it on the return and claim credit for the US federal and state tax?
The employing company has said' ‘For individuals who were resident at vest but not at grant, strictly the award is fully taxable in the UK. However, under treaty provisions a time-apportioned amount relating to the UK may be taxable in the UK. For the purposes of this calculation, we have apportioned the award based upon calendar days’.I shall be very grateful for any help on this matter.

[LozaACCS]

I think the ER statement is not correct, it should say
"for individuals who are resident at vest but not at grant, the options (when vested) are subject to UK IT only if at the time they were granted the award was in respect of UK duties"

[Brightonian]

Thank you for your help. I have been looking at various sources and wonder if either the employer decided that there should be UK tax at the exercise date because the employee already knew that he would be returning to the UK before the award vested or whether they do not regard them as a marketable asset at grant. I have asked him to try to get further information from his HR department or their accountants (Deloittes).