Whether a UK-based Islamic mortgage is halal depends on the specific structure of the financing arrangement and the scholarly opinions you follow. Many Islamic home finance products in the UK are designed to avoid conventional interest (riba) by using models such as Murabaha (cost-plus financing), Ijara (lease-to-own), or Diminishing Musharaka (declining partnership).

However, scholars differ in their views on some modern Islamic finance products, particularly regarding how closely they align with traditional Islamic principles in practice. For this reason, it is important to review the specific contract, understand how the payments are structured, and consult a qualified Islamic scholar or Islamic finance expert who can assess the product in detail.

If you can provide the name of the lender or the specific Islamic mortgage product you are considering, I can offer more detailed information about how it works and the key issues scholars typically examine when determining whether it is halal.