Intro: In Privity, the basic rule states that 3rd parties to a contract can't sue or be sued under a contract ... This restricts 3rd parties as they cannot claim a benefit nor have any liability placed on them.
Cases: "Tweddle v Atkinson". In this case money was to be given on marriage, however Tweddle sued but was found to be unsuccessful as he was suing as a 3rd party. This was later confirmed in the leading case of "Dunlop v Selfridge". In this case an agreement was made between parties not to sell tyres below a given price, it was sold however. It was held that Selfridge couldn't be sued as Dunlop had no direct contact with Selfridge.
AO2: The consequences of the Common Law, mean its a harsh and unfair rule as it allows promises to be broken, as third parties could have acted in reliance and wishes are denied. As a result of this, there have been various exceptions created in order to remedy this injustice, because the common law of Privity is harsh.