CIL framework + Class MA exemption + extension floorspace + London Mayor + borough rates
Community Infrastructure Levy (CIL) under Planning Act 2008 Part 11 + CIL Regulations 2010 (as amended) is a per-square-metre charge on new build residential + commercial floorspace, levied by Charging Authorities (LPAs + Mayor of London) on grant of planning permission. CIL applies to new build floorspace — defined as floorspace created by new construction or extension that did not previously exist in lawful use. CIL does NOT apply to: (a) change of use of existing lawful floorspace (Class MA, Class G, Class O, Class V); (b) demolition + rebuild on same footprint where existing lawful floorspace = proposed floorspace (net zero new floorspace); (c) buildings less than 100m² gross internal area exempt under Regulation 42 (self-build dwelling exemption); (d) social housing (Affordable Housing exemption per Reg 49); (e) charitable use exemption (Reg 43); (f) prior approval routes that authorise change of use only — Class MA, Class G — not chargeable per Reg 5 (only 'planning permissions' are chargeable + prior approval is technically a different consent route per s60(1A) TCPA + Article 7 GPDO + CIL Reg 5 'liable development' definition). Class MA prior approval — settled position post-RWE Innogy v Bonkers Hill 2016 + Brindle v Mid Devon 2017 + DCLG Practice Guidance 2017 + 2024 PPG: Class MA prior approval does not trigger CIL liability on the change-of-use element. Where Class MA is combined with new build extension (e.g. rear extension under Class A.1, mansard extension under full planning, dormer under Class B): CIL applies to the new build extension floorspace only — calculated as proposed extension GIA × Charging Schedule rate. Charging Schedules: each London borough has its own borough CIL Charging Schedule + the Mayor of London Mayoral CIL (MCIL) applies in addition + most boroughs have additional zoned rates by Sub-Area + use class. Typical London borough residential CIL rates 2024 (per m²): Westminster £550 (CAZ) / £200 (rest); Kensington & Chelsea £550 (Knightsbridge etc) / £350 (rest); Camden £500 (Town Centres) / £200; Islington £140 / £45; Hackney £150 / £75; Tower Hamlets £200 / £100; Newham £50 / £30; Lambeth £165; Southwark £200 (Central Activities Zone) / £100; Wandsworth £575 (high value zones) / £250; Lewisham £100 / £45; Greenwich £100; Hammersmith & Fulham £200; Brent £140 / £45; Ealing £125 / £45. Mayoral CIL (MCIL) 2024: Zone 1 (Westminster, K&C, Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Wandsworth, Hammersmith & Fulham) £80/m²; Zone 2 (most outer London boroughs) £60/m²; Zone 3 (outer boroughs Croydon, Bromley, Bexley, Havering, Hillingdon, Sutton) £25/m². MCIL2 surcharge for funding Crossrail 2: not yet in force as of 2026. Affordable housing exempt from CIL (Reg 49). Worked CIL example Class MA + extension: Hounslow Brentford Class MA office (1,180m² to 12 flats) + Class A.1 rear single-storey extension creating 35m² of new ground-floor flat communal kitchen-diner: CIL on extension only 35m² × £80 (Hounslow rate) + 35m² × £60 (MCIL Zone 2) = £2,800 + £2,100 = £4,900 total CIL. Vs full planning route (Article 4 area same conversion + extension) CIL would apply only to extension still (existing 1,180m² is lawful Class E floorspace re-used = no CIL on conversion element).
Section 106 + affordable housing + planning obligations + when applicable + worked savings
Section 106 planning obligations under Town and Country Planning Act 1990 s106 (as amended by Localism Act 2011) are legally enforceable agreements between LPA + developer at point of granting planning permission. Section 106 obligations typically include: (1) Affordable housing contribution — either on-site units or in-lieu commuted sum (typical London 35% affordable housing on 10+ unit schemes); (2) Highway works contribution; (3) Public realm improvements; (4) Education contribution (primary + secondary school places £15,000–£28,000 per child generated); (5) Healthcare contribution (GP capacity + NHS contribution per dwelling); (6) Travel plan; (7) Construction Logistics Plan; (8) Local labour + apprentice schemes; (9) Carbon offset contribution (Mayor of London 2024 £95/tonne CO2 offset for buildings exceeding regulated emissions); (10) Local employment land protection. Section 106 does NOT apply to Class MA prior approval — settled position. Section 106 applies only to: (a) Full planning permissions; (b) Reserved matters approvals; (c) Section 73 variations to full planning permission; (d) Hybrid applications where part is full planning. Class MA + Class A.1 extension: if extension is Class A.1 PD (single-storey rear extension within PD limits) — no full planning so no s106 on extension element. If extension exceeds Class A.1 limits (e.g. 2-storey mansard) — full planning required on extension element + s106 may apply to extension element only (typically negligible for small extensions). Article 4 removal of Class MA: where borough has Article 4 direction removing Class MA + applicant routes via full planning instead — full s106 obligations apply. Typical Section 106 cost London 2024–2026: small Class MA-equivalent full planning conversion (10–18 units): affordable housing 35% (typically commuted sum 3.5–6.3 units × £85,000–£180,000 per unit commuted sum = £298,000–£1,134,000) + carbon offset £8,500–£25,000 + transport £4,500–£12,000 + education £8,500–£35,000 + healthcare £4,500–£12,000 = total Section 106 burden £325,000–£1,200,000 typical 10–18 unit conversion. By avoiding Section 106 via Class MA route savings £325,000–£1,200,000 typical conversion = substantial planning gain advantage of Class MA route. This is exactly why some LPAs use Article 4 to remove Class MA — to capture Section 106 + affordable housing + design control. When Section 106 applies on conversions: (i) Article 4 area + full planning route — full s106 applies (most onerous); (ii) Class MA + Class A.1 PD extension — no s106 on conversion, no s106 on PD extension; (iii) Class MA + full planning mansard/extension — s106 may apply to extension element only; (iv) Class G mixed-use partial conversion — s106 not applicable (prior approval); (v) Hybrid Class MA + Class C3 demolition + new build (e.g. demolish ancillary buildings + replace with mews units) — s106 applies to new build element. Builderr typical cost-comparison Class MA vs Article 4 + full planning (same 12-unit Brentford conversion site): Class MA route: prior approval £258 + consultancy £6,500 + Section 106 £0 + CIL on Class A.1 extension £4,900 = total planning cost £11,658. Full planning route: planning application fee £4,650 + Section 106 affordable housing £535,500 + Section 106 other £45,000 + CIL on extension £4,900 + consultancy £25,000 = £615,050. Saving Class MA route £603,392 per typical conversion = enormous planning gain advantage. Hence Article 4 increasingly used by London boroughs to capture this gain (Tower Hamlets, Hackney, Westminster, K&C, Camden, Islington, Newham, Brent, Lambeth, Southwark partial coverage 2024–2026). Builderr workflow: (1) Acquisition desktop check — Article 4 + Class MA eligibility + scheme economics with/without s106; (2) If Article 4 area — full planning route + s106 negotiation + viability appraisal RICS Code of Practice (often reduces s106 burden 30–60% via VBC + viability); (3) If Class MA available — prior approval + Class A.1 extension if floorspace expansion required + minimal CIL only. See [[class-ma-office-to-residential-conversion-london]] + [[vacant-building-credit-class-ma-london]] + [[cil-vs-section-106-london-residential]] + [[article-4-direction-impact-permitted-development-london]] + [[section-106-vs-cil-london-residential-extensions]].
