ROCK ADVERTISING LTD v MWB BUSINESS EXCHANGE CENTRES LTD
 BLR 479
Before Lady Hale,Lord Wilson,Lord Sumption,Lord Lloyd-Jones,Lord Briggs
“No oral modification” clauses – Whether legally effective – Whether “no oral modification” clauses can be varied orally – Whether intention to vary a “no oral modification” clause is implied from an attempted oral variation of substantive obligations – Analogy with “entire agreement” clauses – Estoppel. – Variations – Consideration – Promises to perform existing obligations – Whether an agreement to pay less or the same money is supported by consideration.