INTM332630 | Double Taxation applications & claims: permanent establishment and special relationship: What the PE provisions are
From HM Revenue & Customs · International Manual
You will have to consider whether the Permanent Establishment condition is satisfied when you give relief under DTAs. Many articles in the DTAs do not allow relief where
the claimant has a Permanent Establishment in the UK
or
the income on the claim is connected with the Permanent Establishment.