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When a handshake isn't enough: contract formation, part performance & proprietary estoppel in commercial negotiations

Tuesday, 24th March 2026
When a handshake isn't enough: contract formation, part performance & proprietary estoppel in commercial negotiations

A recent Irish Supreme Court judgment provides welcome clarity on contract formation, part performance and equitable estoppel in commercial property transactions.

Speedread

In ACE Autobody Limited v Motorpark Limited [2026] IESC 9, the Supreme Court overturned the Court of Appeal's decision and dismissed a claim for specific performance of an alleged agreement to grant a 10-year commercial lease. The judgment reinforces the binding effect of "subject to contract" stipulations in property negotiations and clarifies the limited scope of proprietary estoppel claims in arm's-length commercial transactions. The judgment also serves as a warning that commercial parties who proceed without a concluded contract do so at their own risk and cannot subsequently rely on equity to remedy their position.

Background

The dispute arose from negotiations in 2016 between ACE Autobody Limited (ACE), a motor vehicle repair business, and Motorpark Limited (Motorpark). The principals of ACE and Motorpark went through a term sheet for a proposed 10-year lease of a body shop (the Body Shop) “line by line” and “shook hands” on it in August 2016. Both parties then engaged solicitors to formalise the arrangement. Critically, the solicitors' correspondence was headed "Subject to Lease" (or similar formulations) and ACE's solicitor explicitly stated that no contract would come into existence until approved contracts were "engrossed, executed and exchanged". 

An issue arose over Motorpark's requirement that ACE execute a deed of renunciation, which would have excluded ACE's entitlement to a new tenancy under Part II of the Landlord and Tenant (Amendment) Act 1980. ACE's solicitor objected to this requirement and the renunciation issue was never resolved. Despite legal advice against doing so, ACE took possession of the Body Shop in January 2017 without a concluded lease and incurred substantial fit-out costs. No lease was ever finalised. In 2018, Motorpark decided to sell the premises to a third party and demanded that ACE vacate. 

ACE sought specific performance of the alleged lease agreement and also sought a declaration that it was entitled to a lease on the basis of proprietary estoppel. Motorpark counterclaimed for a declaration that ACE was never more than a licensee and sought an injunction requiring ACE to vacate.

High Court Judgment

The High Court (Owens J) dismissed ACE’s claim, holding that there was no concluded agreement for a 10-year lease.  Owens J found that whilst certain terms had been agreed in August 2016, there was never an overall concluded contract. A significant number of issues remained to be agreed, including the renunciation issue. He noted that the solicitors' correspondence made clear that the principals did not regard themselves as contractually bound.  Owens J characterised the assurances made by Motorpark as "vague comments" which could not amount to a binding assurance.  He rejected ACE's proprietary estoppel claim finding that ACE had "jettisoned" its solicitor's advice and proceeded to go into possession on the "strength of vague assurances", which could not give rise to any form of estoppel.  Owens J held that equity would only supplant contract law in business transactions in limited circumstances and only in exceptional circumstances could equity convert a non-contractual commercial arrangement into a proprietary interest in land. 

Court of Appeal Judgment

The Court of Appeal (Whelan J) allowed ACE’s appeal, holding that a binding agreement existed from September 2016 when the principals "shook hands" on key terms. In her view, all essential terms had been agreed at that stage and solicitors were subsequently engaged "solely for the purposes of putting the concluded agreement into legal shape". She held that the "subject to lease" formulation used by the solicitors had no impact on the terms of the agreement already concluded. The Court of Appeal held that the High Court had erred in failing to attach appropriate weight to ACE's acts of part performance, including taking possession at the instigation and urging of Motorpark. It also upheld ACE's alternative proprietary estoppel claim and ordered specific performance of a 10-year lease.

Supreme Court Decision

The Supreme Court allowed the appeal. Collins J identified three main issues in the proceedings:

1. Contract formation

Collins J reaffirmed the orthodox position that where an agreement is expressed to be "subject to contract" or "subject to lease", "it means what it says" and "the matter remains in negotiation until a formal contract is executed".  The Court held that both parties had expressly stipulated that their engagement was "subject to lease". ACE's solicitor had gone further, stipulating that no contract would come into existence "until such time as approved draft Contracts have been engrossed, executed and exchanged and a contractual deposit paid". No such agreement was ever executed. 

The Court identified two further reasons why no binding agreement arose:

  • A number of essential terms, including the commencement date of the lease, had not been agreed. The Court of Appeal's finding that the lease would commence "as soon as was feasible" was rejected as "simply too vague to satisfy the law's requirements".
  • The parties were never in agreement as to whether ACE would renounce its statutory right to a new tenancy at the end of the term. The Court of Appeal had held that Motorpark was estopped from raising this issue because its solicitor's silence in the face of ACE's objection amounted to a representation that the requirement had been dropped. The Supreme Court disagreed: silence does not, as a general rule, amount to a representation, and there was no evidence that ACE believed the requirement had been abandoned.

More broadly, Collins J found that the Court of Appeal had “gone beyond the permissible bounds of appellate review” (as set out in Hay v O’Grady [1992] IR 210) by effectively conducting a de novo assessment of the evidence (i.e. considering the evidence afresh), rather than identifying errors in the High Court’s reasoning. This meant that the Court of Appeal had “set out an entirely new factual narrative, as if at first instance.”  This serves as an important reminder of the boundaries of appellate review. 

2. Part performance

Collins J emphasised that the doctrine of part performance presupposes the existence of a concluded agreement; “An act of part performance cannot create a contract where there was no contract in the first place”. Since there was no concluded agreement between ACE and Motorpark, ACE’s acts of taking possession, paying rent and incurring expenditure could not assist its claim.

3. Proprietary estoppel

Collins J undertook a detailed analysis of proprietary estoppel case law in Ireland and in England and Wales, drawing a significant distinction between domestic and commercial contexts. 

The Court emphasised that where sophisticated commercial parties negotiate on a "subject to contract" basis, each party assumes the risk that the transaction may not proceed. 

Collins J held that ACE had made a "commercial decision" to enter possession knowing there was no concluded agreement, against its solicitor's advice. ACE thereby took the risk that an agreement for lease would not be agreed. In these circumstances, the High Court was entitled to conclude that ACE had failed to establish any equity that the court should protect. It was not unconscionable for Motorpark to rely on its legal rights in circumstances where there was no concluded contract and where ACE had proceeded with its eyes open to the risk. 

Judgment of Woulfe J

Woulfe J agreed that no concluded agreement existed and that no issue as to part performance arose in such circumstances. However, he differed on the proprietary estoppel issue. He considered that the representations made by Motorpark were clear and unambiguous rather than "vague" as characterised by the trial judge. He was of the view that the overall context demonstrated highly unconscionable conduct sufficient to engage the doctrine of proprietary estoppel. Woulfe J did, however, agree that, even on his analysis, the appropriate remedy would have been a monetary award compensating ACE for its expenditure, rather than an order for specific performance. 

Key Takeaways:

  • "Subject to contract/lease" means exactly that. The Court has reaffirmed that where negotiations are conducted on a "subject to contract/lease" basis, no binding agreement arises until formal contracts are concluded. A handshake or agreement on key terms does not create enforceable rights.
  • All essential terms must be agreed and silence does not equate to agreement. An agreement for lease requires certainty on all essential terms, including the commencement date. A vague expectation that matters will proceed "as soon as feasible" will not suffice. Equally, a solicitor's failure to respond to a query or objection does not amount to acceptance of the other side's position.
  • Proprietary estoppel offers limited protection in commercial contexts. In arm's-length commercial transactions where parties have access to legal advice and negotiate on a "subject to contract/lease" basis, proprietary estoppel will rarely succeed. Sophisticated commercial parties assume the risk that negotiations may fail.
  • Part performance cannot create a contract. The doctrine exists to enforce an oral contract that would otherwise fall foul of statutory formality requirements. It does not bring a contract into existence where none was concluded.
  • Legal advice matters. ACE's decision to proceed against its solicitor's advice was, in the Court's view, "hugely significant". Ignoring legal counsel on contract formation may be fatal to any subsequent claim for equitable relief.

For further information in relation to this topic, please contact Hannah Shaw, Partner,  Simon Barber, Lawyer (Qualified in New Zealand), Aoife Smyth, Practice Development Consultant, Rachel Kemp, Senior Practice Development Lawyer, or any member of ALG's Disputes & Investigations or Real Estate teams.

  • Picture of Simon Barber
    Simon Barber
    Lawyer (Qualified in New Zealand), Disputes & Investigations
  • Picture of Rachel Kemp
    Rachel Kemp
    Senior Practice Development Lawyer, Disputes & Investigations
    Rachel Kemp is a  Senior Practice Development Lawyer in the firm’s Litigation & Dispute Resolution Department.She is an experienced commercial litigator, having previously trained and worked in a large commercial law firm.
  • Picture of Hannah Shaw
    Hannah Shaw
    Partner, Disputes & Investigations
  • Picture of Aoife Smyth
    Aoife Smyth
    Practice Development Consultant, Real Estate