Williams v Roffey Bros [1991]

Defendant, noticing sub-contractor’s difficulties,
offered additional payment for completion.
Court held such promise binding if, as here, promisor
obtained benefit or obviated disbenefit [ie where there was consideration],
provided promise had not been obtained by fraud or duress.
Court cited Pao
On
, inter alia, in support.
[As Anson points out, surely renegotiation would not
automatically have been vitiated by duress if it was sub-contractor who had
taken initiative?]