- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 01 Nov 2020
Contra proferentem is a rule of construction applying to written documents or deeds. The rule provides that if the wording of an agreement is ambiguous or uncertain, but not otherwise, the contract should be construed more strongly against the person whose words they are rather than the other party.
In the case of John Lee & Son (Grantham) Ltd v Railway Executive (1949) it was found that:
'We are presented with two alternative readings of this document and the reading which one should adopt is to be determined, amongst other things, by a consideration of the fact that the defendants put forward the document. They have put forward a clause which is by no means free from obscurity and have contended... that it has a remarkably, if not extravagantly, wide scope and I think that the rule contra proferentem should be applied’
If a party has incorporated its own standard terms and conditions of trade into an agreement then in the event of ambiguity those terms and conditions will be construed contra proferentem that party. Where however the parties execute standard form contracts, the contra proferentem rule will only operate in respect of amendments or additions to the contract.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
Heed advice and insight of this report IPA tells the government.
From the Commonwealth Association of Architects.
For the Levelling Up, Housing & Communities Committee.
BSRIA's Technical Director reflects on recent weather patterns.
A national valuation to fund old-age pensions.
The world’s largest Commonwealth memorial to the missing.
Long after the end of the defects liability period.
Occupant satisfaction and wellbeing in buildings.
From the simple to the complex.
And the UK Government guidelines.
Commitment agreed to by major built environment bodies.
Electrical skills, low carbon, high-tech and the building services revolution.
Ultra-deep drilling with millimeter-wave beam technology.
Looking at the built environment from space.
BSI standards 8671, 8672 and 8673.
Bringing life to burial grounds.
From failed modernism to twenty-minute neighbourhoods.
The gates process and change control.
Why people behave as they do. APM book.