M
Masood
Usually the definition of subcontracting involves the principle of substitution. IE, instead of turning up for work himself, he should be able to send a suitably qualified engineer in his place.
If that is not acceptable, and you require him PERSONALLY to turn up, then you have a "contract of personal service", or in every-day speak, "an employee". You will have the obligations to pay employers NI to HMRC and will be treated by other regulatory bodies as employer/employee, regardless of what you and he agree between you.
Whilst that is true of most contractor/consultant type roles after IR35, CIS rules define contracting within the construction industry differently. As has been correctly pointed out already, the defining criterion is mainly one of exclusivity and autonomy:
Does he work only for you, or to such a large percentage of his time that it could be considered exclusive?
Do you explicitly instruct him, or dies he have autonomy in deciding how to structure the work and his time spent doing it?
Do you provide all materials or does he provide some and bill you for them?
There are other rules but these are the main ones. I'm happy to be corrected if I'm wrong but I've done a lot of reading of the CIS website, spoken with my accountant and with HMRC about CIS contractors as I did not want to fall foul of the rules...