Lord Bingham said,

‘8. I consider first the proper construction of this release. In construing this provision, as any other contractual provision, the object of the court is to give effect to what the contracting parties intended. To ascertain the intention of the parties the court reads the terms of the contract as a whole, giving the words used their natural and ordinary meaning in the context of the agreement, the parties’ relationship and all the relevant facts surrounding the transaction so far as known to the parties. To ascertain the parties’ intentions the court does not of course inquire into the parties’ subjective states of mind but makes an objective judgment based on the materials already identified. The general principles summarised by Lord Hoffmann in Investors Compensation Scheme Ltd v West Bromwich Building Society …apply in a case such as this.’

[Edited for ease of reading. You can find the original case on Westlaw].