Splitting scope between an architect and a planning agent

On a householder extension the architect designs the building and draws it. The planning agent reads the local plan, writes the supporting statements, fills in the forms and deals with the case officer. On most small jobs one firm does both, which is fine, and the trouble starts when two firms are involved and neither has written down where one stops and the other starts.

Settle two questions before anything is submitted. Who produces each drawing and each written document, and whose name goes in the agent box on the application form. Everything else follows from those.

What each role covers

An architect is someone on the Architects Registration Board's register, because the title is protected by the Architects Act 1997. An architectural technologist, an architectural designer or a chartered surveyor may do the same work on a house extension without that title, and for a rear extension on a 1930s semi the distinction rarely changes the outcome. What all of them produce is the same package: a measured survey of what is there, drawings of what is proposed, a materials schedule, and later the Building Regulations information.

A planning agent works on the policy side. They check whether the proposal is permitted development or needs an application, identify the constraints on the site, read the adopted local plan and any householder design guide, and write the narrative that explains why the scheme complies. The title planning consultant is not protected, so chartered membership of the Royal Town Planning Institute is the usual marker of training and a disciplinary code behind it. The note on what chartered membership of the RTPI actually means sets out what the letters do and do not tell you.

Who prepares which document

The Design and Access Statement row catches people out. Article 9 of the Town and Country Planning (Development Management Procedure) (England) Order 2015 requires one for major development, and in a conservation area or World Heritage Site for development involving one or more dwellings or 100 square metres or more of floorspace, and for listed building consent. A single-storey rear extension on an unlisted house outside a conservation area needs no such statement, whatever a template pack tells you. Councils can ask for design information through their local validation list, which is a different thing and worth checking on the authority's website before either consultant starts writing.

Who is named as agent on the form

The agent box on the application form decides who receives correspondence. Once an agent is named, the council sends the validation email, the consultation responses, the request for further information and the decision notice to that person, and it will generally not copy the applicant in. If your designer is named but your planning agent is running the negotiation, the planning agent finds out about a problem second hand, and sometimes a week late.

Name one of them. The other gets copied in by agreement rather than by the system. And if you change agent mid-application, tell the case officer in writing, because the portal record does not update itself.

Ownership certificates are the applicant's responsibility in substance even when the agent signs them. Certificate A applies where the applicant owns the whole site. Certificates B, C and D cover cases where someone else owns part of it, and they trigger a notice requirement. Get this wrong on a shared driveway or a garden strip that was never formally transferred, and the permission can be vulnerable later.

Where design and policy overlap

The justification for a design is the one document neither role can write alone. A planning agent can quote the policy that asks for extensions to be subordinate to the host dwelling. Only the designer knows why the ridge was set 400 millimetres below the main roof, why the rear elevation uses a different brick bond, and what the alternative options were before this one was chosen.

The way through is a short design rationale written by the designer, three or four paragraphs, which the agent then folds into the planning narrative with the policy references attached. That takes an hour of the designer's time and saves the agent inventing reasons the design team never had. It also avoids the problem set out in the piece on conflicts of interest when your designer writes the reports, where the person defending the scheme is the same person who produced it.

Fees and where duplication creeps in

Duplication has three usual homes. The first is the site appraisal: both consultants check the constraints, both charge for it. The second is the pre-application meeting, where two people attend and only one speaks. The third is the response to objections, which the designer drafts, the agent rewrites, and the client pays for twice.

Ask each for a fixed fee against a written scope rather than an hourly rate against a vague one. On a householder scheme the planning side is usually a smaller number than the design side, and quotes in the range of £500 to £2,500 for a planning statement are common, which makes it worth knowing whether you actually need one.

The application fee itself is separate and goes to the council. It is set by national regulations and indexed annually, so check the current figure on the Planning Portal rather than a number from an older quote.

Handover points in the programme

1. Feasibility. Designer sketches options, agent advises which are likely to be acceptable in policy terms. Both inputs, one meeting.
2. Pre-application advice, if the council offers it. The agent leads and the designer supplies the drawings.
3. Design freeze. Nothing after this point changes without both being told.
4. Document preparation. The agent writes the statements against the frozen drawings.
5. Submission. The named agent uploads and pays, and confirms the reference number to everyone.
6. Determination. The agent handles consultation responses and officer queries, going back to the designer for amendments.
7. Decision. Conditions are read by both, because conditions that must be discharged before work starts usually need information the designer holds.

Step three is where most small projects come unstuck. A drawing revised after the statements are written leaves a document describing a building that no longer exists, and a case officer who spots it loses confidence in the whole submission.

Putting the split in writing

A single page is enough. List each deliverable, name the person responsible, note who is the agent on the form, and say who pays the application fee. Add a line on what happens if the council refuses: whether the agent's fee covers an appeal, or whether that is a new instruction.

If a specialist report becomes necessary, an arboricultural or ecology report for instance, decide immediately who commissions and who reviews it. Neither the designer nor the agent should be signing off a technical report outside their competence, and the guidance on reviewing a specialist report you did not commission sets out what a sensible check looks like. Where a report needs a licensed or competent professional, that person must be properly qualified, and PlanScope's professional directory exists for exactly that sign-off step.

You can draft the planning narrative yourself and have it checked. Enter your postcode on PlanScope to see which reports a householder scheme is likely to need before you agree scope with anyone.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.