The concept of ordinary residence has largely been abolished for tax purposes from 6 April 2013. Instead, residence is to be determined on a statutory basis by the Statutory Residence Test (SRT). HMRC will be launching an online tax residence indicator, which will run through a series of questions (eg how many days the taxpayer spent in the UK, what family ties they have) to give an indication as to their residency.
For HMRC’s published guidance on the SRT and Overseas Workday Relief, see:
Guidance Note: Statutory Residence Test (SRT)
Guidance Note: Overseas Workday Relief (OWR)