Data Sources of Record

Every numeric claim on this site is tied to one of the primary sources below. Verified 2026-07-25. Re-verified quarterly; see the changelog for the audit log.

BCIS General Building Cost Index Q2 2026

Owner: RICS · Vintage: Q2 2026

BCIS General Building Cost Index Q2 2026· Q2 2026

National Planning Policy Framework, Dec 2024 (amended Feb 2025)

Owner: MHCLG · Vintage: Dec 2024 (amended Feb 2025) in force; revised NPPF in draft, final expected Summer 2026

National Planning Policy Framework, Dec 2024 (amended Feb 2025)· Dec 2024 (amended Feb 2025) in force; revised NPPF in draft, final expected Summer 2026

Planning Practice Guidance: Viability

Owner: MHCLG · Vintage: Current online guidance (aligned to NPPF Dec 2024); suggests 15-20% of GDV developer return

Planning Practice Guidance: Viability· Current online guidance (aligned to NPPF Dec 2024); suggests 15-20% of GDV developer return

RICS Valuation Global Standards (Red Book)

Owner: RICS · Vintage: Effective 31 Jan 2025

RICS Valuation Global Standards (Red Book)· Effective 31 Jan 2025

HM Land Registry Price Paid Data

Owner: HM Land Registry · Vintage: Q1 2026 release

HM Land Registry Price Paid Data· Q1 2026 release

Stamp Duty Land Tax (SDLT)

Owner: HMRC · Vintage: Current rules post-31 Mar 2025

Stamp Duty Land Tax (SDLT)· Current rules post-31 Mar 2025

Land and Buildings Transaction Tax (LBTT)

Owner: Revenue Scotland · Vintage: 2026/27 bands

Land and Buildings Transaction Tax (LBTT)· 2026/27 bands

Land Transaction Tax (LTT) Wales

Owner: Welsh Revenue Authority · Vintage: 2026/27 bands

Land Transaction Tax (LTT) Wales· 2026/27 bands

Community Infrastructure Levy

Owner: DLUHC (MHCLG) · Vintage: Current statutory regime

Community Infrastructure Levy· Current statutory regime

Biodiversity Net Gain guidance

Owner: Defra · Vintage: Statutory since 12 Feb 2024 (major sites) and 2 Apr 2024 (small sites); new 0.2ha small-site exemption and removal of self-build exemption from 6 Aug 2026

Biodiversity Net Gain guidance· Statutory since 12 Feb 2024 (major sites) and 2 Apr 2024 (small sites); new 0.2ha small-site exemption and removal of self-build exemption from 6 Aug 2026

Permitted Development Rights

Owner: DLUHC (MHCLG) · Vintage: Class MA and Q current

Permitted Development Rights· Class MA and Q current

Technical Housing Standards (NDSS)

Owner: DLUHC (MHCLG) · Vintage: Applies to PDR conversions from 6 Apr 2023

Technical Housing Standards (NDSS)· Applies to PDR conversions from 6 Apr 2023

HMRC VAT431NB DIY housebuilders reclaim

Owner: HMRC · Vintage: Digital portal active

HMRC VAT431NB DIY housebuilders reclaim· Digital portal active

UK Finance data and research

Owner: UK Finance · Vintage: Q1 2026

UK Finance data and research· Q1 2026

Bank of England statistics

Owner: Bank of England · Vintage: Current bank rate 3.75 percent (held 30 Jul 2026)

Bank of England statistics· Current bank rate 3.75 percent (held 30 Jul 2026)

ONS construction output inflation

Owner: ONS · Vintage: Latest monthly

ONS construction output inflation· Latest monthly

UK House Price Index

Owner: HM Land Registry / ONS · Vintage: April 2026 release

UK House Price Index· April 2026 release

Mayoral CIL2 Annual CIL Rate Summary 2026

Owner: Greater London Authority · Vintage: 2026-indexed rates (Ip=400/Ic=330): Band 1 £96.97, Band 2 £72.73, Band 3 £30.30 per sqm

Mayoral CIL2 Annual CIL Rate Summary 2026· 2026-indexed rates (Ip=400/Ic=330): Band 1 £96.97, Band 2 £72.73, Band 3 £30.30 per sqm

BCIS General Building Cost Index Q2 2026· Q2 2026Appraisal model reviewed by Oliver Wakefield-Smith (data integrity) with chartered-surveyor (MRICS) and CTA tax review. No affiliate links.