Best endeavours v reasonable endeavours
Many construction industry practitioners will have been confronted with a contract which requires the parties to use 'best' or 'reasonable' endeavours in performing obligations under the contract. This apparently minor difference however presents a real risk to a party if they are unaware of the difference in legal interpretation between the two terms.
Evidently an obligation to use 'best endeavours' implies a higher degree of commitment to perform a particular task when compared to 'reasonable endeavours' but, as is often the case, it is only when a contract dispute arises and Court proceedings follow that the reality of the difference becomes apparent.
There are no clear definitions of these terms upon which reliance can be made but case law has held that best endeavours means, amongst other things:
- To leave no stone unturned.
- To do what is reasonably to be expected in the circumstances.
- Not to do anything that will jeopardise the commercial interests of the obligor.
An immediate and obvious difficulty is that the word “reasonably” appears in a definition of 'best' endeavours. Furthermore, case law has also used similar language in defining reasonable endeavours.
Behind these definitions lies an expectation of what might be done to ensure that these obligations are met.
In the case of best endeavours it may be the case that a party has to commit extra resources or spend additional funds in order to meet the obligation, even to the extent that it is commercially damaging to the party concerned. Where the obligation is reasonable it is unlikely that this degree of obligation would be applied by the Courts.
And when it comes to testing these definitions in Court a subjective approach is adopted for best endeavours whilst it is an objective one for reasonable endeavours.
For the purposes of the layman, however, one can point to certain more simple facts:
- Reasonable endeavours will be less onerous than best endeavours.
- If a contract sets out specific steps to be taken as part of a reasonable obligation, ensure that these steps are indeed carried out. This is regardless of commercial considerations.
This article was created by: --Martinc 14:11, 22 November 2014 (UTC)
[edit] Related articles on Designing Buildings Wiki
- Delict.
- Duty of care.
- Duty to warn.
- Fitness for purpose.
- Good faith.
- Good faith – good grief.
- Reasonable skill and care.
- Unreasonable.
[edit] Relevant case law
Featured articles and news
Costs and insolvencies mount for SMEs, despite growth
Construction sector under insolvency and wage bill pressure in part linked to National Insurance, says report.
The place for vitrified clay pipes in modern infrastructure
Why vitrified clay pipes are reclaiming their role in built projects.
Research by construction PR consultancy LMC published.
Roles and responsibilities of domestic clients
ACA Safety in Construction guide for domestic clients.
Fire door compliance in UK commercial buildings
Architect and manufacturer gives their low down.
Plumbing and heating for sustainability in new properties
Technical Engineer runs through changes in regulations, innovations in materials, and product systems.
Awareness of the Carbon Border Adjustment Mechanism
What CBAM is and what to do about it.
The new towns and strategic environmental assessments
12 locations of the New Towns Taskforce reduced to 7 within the new towns draft programme and open consultation.
Buildings that changed the future of architecture. Book review.
The Sustainability Pathfinder© Handbook
Built environment agency launches free Pathfinder© tool to help businesses progress sustainability strategies.
Government outcome to the late payment consultation, ECA reacts.
IHBC 2025 Gus Astley Student Award winners
Work on the role of hewing in UK historic conservation a win for Jack Parker of Oxford Brookes University.
Future Homes Building Standards and plug-in solar
Parts F and L amendments, the availability of solar panels and industry responses.
How later living housing can help solve the housing crisis
Unlocking homes, unlocking lives.
Preparing safety case reports for HRBs under the BSA
A new practical guide to preparing structural inputs for safety cases and safety case reports published by IStructE.
Male construction workers and prostate cancer
CIOB and Prostate Cancer UK encourage awareness of prostate cancer risks, and what to do about it.





















