South Dublin County Council v Threshford Ltd and Ors, O'Neill v Branach Developments Ltd and Anor

• Jurisdiction: Ireland
• Court: High Court
• Judge: Humphreys J.
• Judgment Date: 03 June 2026
• Neutral Citation: [2026] IEHC 342
• Docket Number: [High Court Record No.: H.CA.2025.0000329] [Circuit Court Record No.: 2025 5748 Co. Dublin] [Circuit Court Record No.: 2025 5894 Co. Dublin]

In the Matter of the Planning and Development Act 2000

Notice of Motion for Relief Under Section 160 of the Planning and Development Act 2000

Between

South Dublin County Council

Respondent/Plaintiff

and

Threshford Limited, Mullnassa Limited and Branach Developments Limited

Appellants/Defendants

In the Matter of the Planning and Development Act 2000

Notice of Motion for Relief Under Section 160 of the Planning and Development Act 2000

Between

John O'Neill

Applicant/Respondent

and

Branach Developments Limited and Mullnassa Limited

Respondents/Appellants

[2026] IEHC 342

[High Court Record No.: H.CA.2025.0000329]

[High Court Record No.: H.CA.2025.0000330]

[Circuit Court Record No.: 2025 5748 Co. Dublin]

[Circuit Court Record No.: 2025 5894 Co. Dublin]

THE HIGH COURT

PLANNING & ENVIRONMENT

CIRCUIT APPEAL

DUBLIN CIRCUIT

COUNTY OF THE CITY OF DUBLIN

JUDGMENT of Humphreys J. delivered on Wednesday 3 June 2026

“Two photographs probably best encapsulate what this case is about.

1 . This is a particularly egregious case of disregard of planning law. It is not made any better by the non-reality-based sworn evidence on behalf of the respondents that, like the Party's final and most essential command in Orwell's Nineteen Eighty-four (London, Secker & Warburg, 1949), pt. 1 §7, “told you to reject the evidence of your eyes …”. Nor are matters improved by the fact that the unauthorised works have occurred in a highly sensitive setting – zoned “High Amenity – Dublin Mountains” in the South Dublin County Development Plan 2022–2028, with the objective to “protect and enhance the outstanding natural character of the Dublin Mountains Area”. Nor is the situation made better by the almost unbelievable chutzpah of the developers who even now claim “innocent mistake”, even though they ignored or deflected warning letters and intensified construction of the unauthorised development in the teeth of interventions from the council and residents and during the course of proceedings before the Circuit Court. This is as far from innocence as you can get – this was an attempt to create a fait accompli with a view to turning around and defiantly asking the system, in effect, “what are you going to do about it?”. I suppose like many other people who defy planning law, the respondents are now going to find out.

2 . The old adage is that when the facts are against you, hammer the law – and nobody could take from the vigour of the hammering resorted to by the respondents in that regard. While a superhuman jurisprudential effort has been made on behalf of the respondents to advance any conceivable reason as to why the facts should not lead to an adverse order, that exercise, while at one level enormously impressive, is, unpersuasive. As the council submitted, “this isn't a marginal case”. The ultimate reason for that is that while ornate scholarly infrastructure was totteringly erected by the respondents in a majestic doctrinal exercise by way of defence, none of this arises on the facts and therefore none of this makes any difference to anything. What defeats the respondents is not some abstruse point of law that cries out for clarification, but the egregious nature of their own conduct and the inevitably adverse factual findings that flow from that.

Judgment history

3 . A 1972 permission required the removal of caravans within one year, but this was not complied with. It also prohibited additional caravans. When the council sought to enforce this against the previous owner Mr Hill, they were unsuccessful: Dublin County Council v. Hill [1994] 1 I.R. 86, [1992] I.L.R.M. 397 per McCarthy J. ( ex tempore, O'Flaherty and Egan JJ. concurring).

4 . During the Circuit Court proceedings, the appellants issued judicial review proceedings seeking to restrain s. 160 proceedings but apparently without disclosing the existing s. 160 proceedings on the papers ( Threshford Limited and Mullnassa Limited v South Dublin County Council [Record No. 2025 1624 JR]). The appellants, the first time the matter was before the court, applied to withdraw those proceedings. Notwithstanding the application to withdraw the said proceedings the council sought to address the High Court (Holland J.), and I deal with this further below. Ultimately the judicial review application was struck out.

5 . Section 160 injunctions were granted by HH Judge O'Connor on 19 December 2025, and the respondents appeal from those orders.

Geographical context

6 . The proceedings comprise an appeal by the first and second named appellants against a s. 160 order made by Dublin Circuit Court on 19 December 2025 and perfected on 22 December 2025 in relation to lands located at Chianti Park, Mount Seskin Road, Raheen, Brittas, Co Dublin, at: https://maps.app.goo.gl/5TAAWEjDT1VqLmDMA. The lands are zoned “High Amenity—Dublin Mountains (HA-DM)” in the South Dublin County Development Plan 2022–2028.

7 . The property the subject of these proceedings can be viewed on Google Street View using https://maps.app.goo.gl/pnLXdfk8VTya5ALaA. An aerial photo of the property from Google Maps can be accessed at https://maps.app.goo.gl/2S42xG7Vq8QWkVq36.

8 . Next door to Chianti Park is a development called Hillbrook Lawns which is a similar caravan/ mobile home park since 1968. The respondents say that the next door park demonstrates that the modular dwellings may be of a superior type of structure to caravans/ mobile homes for the purposes of living conditions.

Parties

9 . The plaintiff/respondent, South Dublin County Council, is the relevant planning authority.

10 . John O'Neill is the applicant/plaintiff in these proceedings. He lives c. 200 m from the property the subject of these proceedings.

11 . As to the respondents, Threshford Limited, of College House, 71/73 Rock Road, Black Rock, Co. Dublin (A94 FPXP), is the owner and/or occupier of the lands and/or is the entity responsible for carrying out the development the subject of proceedings pursuant to s. 160 of the Planning and Development Act 2000 (the 2000 Act).

12 . Mullnassa Limited, of College House, 71/73 Rock Road, Black Rock, Co. Dublin (A94 FPXP), is the owner and/or occupier of the lands and/or is the entity responsible for carrying out the development the subject of proceedings pursuant to s. 160 of the 2000 Act.

13 . Branach Developments Limited, of Thomastown, Caragh, Kildare, Ireland, is the entity carrying out the development on the lands on behalf of the first and second named appellants.

Facts – SDCC case

14 . The alleged unauthorised development, the subject matter of these proceedings, gave rise to a series of complaints from mid-August 2025 to mid-September 2025.

15 . On 18 August 2025, pursuant to s. 152 of the 2000 Act, the council issued warning letters to Mr Hill (the previous owner of the lands) and the third named appellant.

16 . The previous owner responded to the said warning letter, indicating he was no longer the owner of the lands.

17 . The third named appellant responded to the council by letter dated 12 September 2025, indicating that whilst they were carrying out the works on the lands, it was at the request/instruction of the owner.

18 . The council subsequently issued a letter to various parties, including the appellants herein, prior to proceedings. Dated 30 September 2025, same sought for the unauthorised development to cease immediately, as well as other specific undertakings.

19 . The third named appellant replied to the said letter, by way of correspondence dated 1 October 2025, and again disputed any responsibility for the unauthorised development.

20 . In response to this correspondence, the council wrote to the third named appellant on 1 October 2025, asking it to clarify who the owner of the lands was or who it was working for. By way of further letter, dated 1 October 2025, the third named appellant failed and/or refused to provide this information.

21 . On 2 October 2025, the council received correspondence from solicitors acting for the first and second named appellants. This correspondence indicated that they were seeking time to take instructions.

22 . The council responded to the said correspondence by email dated 3 October 2025, indicating that it would extend time for any undertakings to 6 October 2025 at 2 pm.

23 . On 7 October 2025, the solicitor for the first and second named appellants responded to the council's correspondence and indicated, for reasons set out, that the appellants' position was that the allegation of unauthorised development was “misconceived” and the development was exempt pursuant to s. 4(1)(h) of the 2000 Act.

Facts – O'Neill case

24 . The lands the subject of these proceedings are known as Chianti Park, Mount Seskin, Brittas, County Dublin, also referred to as Hillsbrook Lawn, and are situated within the administrative area of South Dublin County Council. The property comprises a former caravan, mobile home and chalet site and is owned by the respondents.

25 . The applicant resides in close proximity to the property and has done so for a number of years. The applicant's dwelling is located approximately 200 m from the property.

26 . The property was originally in agricultural use. From 1968, allegedly, the property was used for mobile homes and chalets. Planning permission was granted in or about 1972 for the retention of a limited number of mobile homes, subject to conditions including a requirement that the structures be removed within one year and that no further such structures be erected.

27 . Over time, the number of structures on the property increased beyond what was originally permitted, and there has been a history of unauthorised development on the property.

28 . On or about 11 August 2025, works commenced on the property which are the subject of these proceedings.

29 . The works the subject matter of these proceedings are works for the maintenance, improvement or other alteration of existing...