40 Northiam London N12 7HJ

1. 20 Oct 2025

   Received by Barnet

2. 17 Nov 2025

   Decision issued: Lawful

3. 10 Aug 2026

   Added to PlanIndex

The council has decided this application; the published outcome sits in the record above and the decision notice on the council portal carries the detail, including any conditions.

If permission was granted, work must normally begin within three years of the decision. If it was refused, the applicant can appeal within the statutory time limit or submit a revised scheme.

A lawful development certificate is a legal determination, not a planning judgement. It asks the council to confirm either that existing use or works are lawful, often through the passage of time, or that a proposal would not need planning permission at all. The applicant must prove the facts; the merits of the scheme are not considered.

More on lawful development applications in our guide

• 40 Northiam London N12 7HJ

  26/0613/HSE Submitted 17 Feb 2026 0m away

  Single storey side and rear extension including alteration to the existing access steps following demolition of the side garage and rear outbuilding

  Refused Householder Extension Demolition 14 docs
  Small domestic

• 40 Northiam London N12 7HJ

  25/4397/PNH Submitted 4 Nov 2025 0m away

  Single storey rear and side extension with a proposed depth from the rear wall of 4.00m, maximum height of 3.00m and eaves height of 3.00m following the demolition of the existing side extension and shed

  Refused Prior approval Extension Demolition 6 docs
  Small domestic

• 71 Southover London N12 7HG

  26/0983/HSE Submitted 16 Mar 2026 47m away

  77% historically approved · decision due ~15 Jun

  Conversion of garage into habitable room including insertion of windows to replace existing garage doors and addition of new pitched roof with rooflight. Two storey side extension following demolition of existing store. Roof extension including 1no. side dormer window, 1no. rear dormer window and 2no. front facing rooflights and increase in ridge height. Installation of solar panels. Alterations to ground floor rear projection including changes to fenestration and insertion of rooflights to flat roof. Addition of 1no. AC condenser unit and 1no. Air Source Heat Pump to side elevation. Removal of chimneys

  Awaiting decision Householder Extension Loft or dormer +3 6 docs
  Domestic

• 40 Northiam London N12 7HJ

  26/2250/HSE Submitted 16 Jun 2026 90m away

  77% historically approved · decision due ~11 Aug

  Single storey side and rear extension including 3no. flat rooflights and alteration to the existing access steps following demolition of the side garage and rear outbuilding

  Decided Householder Extension Loft or dormer +1
  Several homes

• 58 Northiam London N12 7HJ

  25/4079/HSE Submitted 10 Oct 2025 91m away

  77% historically approved · decision due ~8 Dec

  Part single, part two storey front, side and rear extensions following demolition of existing garage and ground floor side and rear extension. Insertion of 1no. new first floor window to flank elevation. Alterations to front steps. New front porch. Alterations to rear patio

  Awaiting decision Householder Extension Demolition +1 20 docs
  Small domestic

• 58 Northiam London N12 7HJ

  25/4786/HSE Submitted 1 Dec 2025 91m away

  77% historically approved · decision due ~27 Jan

  Part single, part two storey front, side and rear extensions including alterations to front steps. new front porch and alterations to rear patio following demolition of existing garage and ground floor side and rear extension. Insertion of 1no. new first floor window to flank elevation.

  Awaiting decision Householder Extension Demolition +1 15 docs
  Small domestic

• 26/1907/191 Decided

  8 Golders Manor Drive London NW11 9HT

  Use of the property as a self-contained residential unit at ground floor level and the first and second floors as a 4-bedroom, 4-person House in Multiple Occupation (Sui Generis) (AMENDED DESCRIPTION)

  21 May 2026 Lawful development
• 26/2059/192 Decided

  Low Ridge Rowley Lane Barnet EN5 3HS

  Erection of a rear outbuilding

  3 Jun 2026 Lawful development
• 26/2066/192 Decided

  355 Hendon Way London NW4 3NB

  Roof extension involving rear dormer window and 3no. front facing rooflights. Removal of chimney on rear elevation (AMENDED DESCRIPTION)

  3 Jun 2026 Lawful development
• 26/1663/192 Decided

  152 Deans Lane Edgware HA8 9NT

  Change of use from single family dwellinghouse (Class C3a) to supported living accommodation Class C3b)

  5 May 2026 Lawful development
• 26/2025/192 Decided

  18 Hale Drive London NW7 3DU

  Roof extension involving hip to gable, rear dormer window, 2no. front facing rooflights and new side gable window

  1 Jun 2026 Lawful development