A subcontractor is someone who undertakes specialist activities in relation to the R&D on behalf of the company claiming R&D Tax credits.

Externally provided workers are staff employed by the company through an employment agency but also includes staff supplied by another related or group company.

For R&D purposes the relief on the costs is the same, relief is restricted to 65% if they are unconnected or 100% if they are connected or an election is made to treat them as connected.