17-17A Mill Lane Welwyn AL6 9EU

1. 3 Aug 2026

   Received by Welwyn Hatfield

2. 5 Aug 2026

   Validated

   Checked as complete and ready for consideration.

3. 15 Aug 2026

   Added to PlanIndex

4. Decision

   Awaiting decision

   Decision expected by 30 September 2026, 8 weeks from validation under the statutory target for most applications. Extensions of time are common and are agreed case by case.

   Welwyn Hatfield took a median of 58 days over the applications it decided in the last year.

This application is with Welwyn Hatfield for determination. The council publicises it, consults neighbours and technical bodies where required, and weighs the responses against local and national planning policy.

The statutory target is eight weeks for most applications and thirteen for major development, though extensions of time are common. Comments carry most weight while the case is undecided, so check the council portal for the deadline if you want to respond.

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

• 17-17a Mill Lane Welwyn AL6 9EU

  6/2026/0443/PN29 Submitted 11 Mar 2026 0m away

  Change of use of offices to 3 x 2 bedroom flats

  Decided Prior approval New dwelling

• 23-25 Mill Lane Welwyn AL6 9EU

  6/2026/0263/COND Submitted 16 Feb 2026 31m away

  Submission of details pursuant to condition number 2 (Material details) on planning permission 6/2025/1211/LB

  Granted Conditions 1 doc

• 23-25 Mill Lane Welwyn AL6 9EU

  6/2026/0262/COND Submitted 16 Feb 2026 31m away

  Submission of details pursuant to condition number 5 (Material details) and 6 (Hard and soft landscaping) on planning permission 6/2025/1212/HOUSE

  Granted Conditions
  Major scheme

• 1 Mimram Walk Welwyn AL6 9EZ

  6/2022/2721/TC Submitted 1 Dec 2022 34m away

  Weeping Beech in rear garden to south of property. 30% Crown reduction to balance

  Granted Trees

• The White Horse 30 Mill Lane Welwyn AL6 9ET

  6/2024/1409/FULL Submitted 24 Jul 2024 44m away

  Retrospective application for the erection of 4no. timber framed garden pods with polycarbonate roof to the rear garden, use of part of the existing rear storage outbuilding to garden bar servery, retention of the existing stretched tent located to the rear of the premises

  Granted Full applications

• 5 Mill Lane Welwyn AL6 9EY

  6/2024/2050/TC Submitted 23 Oct 2024 53m away

  Remove 1 x Beech tree

  Granted Trees

• 6/2026/0735/LAWE Refused

  1 Northaw Place Coopers Lane Northaw Potters Bar EN6 4NQ

  Certificate of lawfulness for the existing use of the land as residential garden land ancillary to the dwellinghouse continuously since 2012

  27 Apr 2026 Lawful development
• 6/2026/1132/LAWE Refused

  19 Cunningham Avenue Hatfield AL10 9LR

  Certificate of existing lawfulness of a 5 person HMO since 6 April 2006

  30 Jun 2026 Lawful development
• 6/2026/1506/LAWP Awaiting decision

  Gosmore Brocket Road Welwyn Garden City AL8 7TT

  Erection of single storey side extensions x 2 and two storey rear extension

  27 Aug 2026 Lawful development
• 6/2026/1503/LAWE Awaiting decision

  27 Batterdale Hatfield AL9 5JG

  Certificate of lawfulness for the existing like-for-like replacement of damaged and aged windows on the front and rear elevations

  26 Aug 2026 Lawful development
• 6/2026/1044/LAWP Granted

  5 Peartree Court Welwyn Garden City AL7 3XN

  Certificate of lawfulness for the change of use from C3 (dwellinghouse) to C4 (HMO for up to 6 unrelated residents)

  15 Jun 2026 Lawful development