The evidence must address the policy for the particular use and location. There is no single marketing period that applies to every London commercial property, and an empty building is not automatically proof that its use is no longer viable. [1][2]
Find the policy before starting the marketing
Establish the lawful existing use, the applicable policy designation and whether a full planning application is needed. A genuine switch within Class E is different from an application to replace employment space with homes. Marketing requirements associated with a full application should not automatically be imported into an unrelated permitted-development test. [3][4][1]
The council may be interested in retaining the existing use, another employment use, a community facility or an active commercial frontage. These are different questions and can call for different evidence. An agent instructed only to test the owner's preferred disposal terms may not have investigated the alternatives the policy asks about. [1]
What credible evidence looks like
Camden's published guidance asks for an account of the marketing exercise and viability of the relevant use. A useful evidence file records the property offered, dates, advertising channels, terms, enquiries and the reasons offers did not proceed. The asking price or rent needs justification against the market rather than being set simply to reflect the value of a hoped-for residential permission. [1]
Prepare the marketing brief with the policy in front of you. Keep dated copies of advertisements and a consistent enquiry log. Explain limitations such as condition, access or servicing, and distinguish the cost of making the premises usable from the value of a different redevelopment scheme. These are evidence-management steps, not a guarantee that the council will agree that the use can be lost. [1]
Examples of different periods
For the loss of employment use, Camden's published requirements include marketing evidence covering two years and evidence on viability for the existing and alternative employment uses. This is a Camden requirement, not a national two-year rule for every vacant office. [1]
The NPPF published on 17 August 2026 includes policy HC6 on the loss of community facilities. For shops and pubs, its retention test refers to unsuccessful marketing of the existing use for at least 12 months when demonstrating lack of commercial viability. HC6 also contains alternative considerations concerning replacement facilities and other local provision. It should not be reduced to “advertise for a year and permission follows”. [2]
Vacancy and Article 4 do not decide the application
An Article 4 direction removing Class MA can make a full planning application necessary, but it does not itself prove that commercial retention is justified or that conversion must be refused. The application still needs to address the relevant policies and evidence. [5][3]
Equally, a long vacancy does not substitute for evidence of realistic and effective marketing where that is required. Establish what the council expects before relying on a marketing history that may not answer the policy test. [1]
Policy changes to keep under review
London's replacement plan remained a consultation draft on 2 October 2026. Check emerging policies alongside the adopted policies when preparing a long-running marketing and conversion strategy, without presenting draft requirements as already adopted. [6]