By way of contrast, however, given that the core of personal bar in Scots law lies in the idea of inconsistent conduct and unfairness, the idea of promise seems largely, perhaps wholly, irrelevant to the doctrine. Because of the comparative ease with which contractual promises and unilateral promises can be expressly enforced in Scotland, the field lying beyond these enforceable obligations within which personal bar operates does not, for the most part, include cases which have a promissory aspect but which simply fail to meet the requirements for a contract, as is the case with promissory estoppel in the Common law.

Liability in Scots law (based on the Walker v. Milne line of cases) for pre-contractual statements which give the impression that a contract has been concluded, when it has not, was discussed in Chapter 3.67 Such liabil­ ity is best not seen as a form of personal bar as such, given that what is claimed is wasted expenditure from failure to constitute a valid obligation rather than prevention of conduct inconsistent with a validly established obligation.

(c)  German law

German law does not require mutual consideration for a contract to be binding. It also treats offers as binding unless they are stated to be other­ wise. These features of contract law mean that many of the cases which in the Common law require the application of promissory estoppel, includ­ ing variations to contracts, can be solved in an ordinary contractual man­ ner in German law, as discussed earlier in this chapter.

In addition, German law also recognises that a party should not be entitled to go against its own prior conduct, a German manifest­ ation of the Roman venire contra factum proprium doctrine known as Verwirkung or, in English, ‘forfeiture’, based upon the idea of good faith.68 Some of the German cases of Verwirkung can be compared to promissory estoppel in the Common law, as in some the previous conduct was a promise made to another (as for instance in the case of a lawyer who was held not entitled to charge more than the amount he had suggested on a prior occasion69), but others have more of the

67See discussion in Ch. 4, pp. 197ff.

68For a full treatment, see Singer, Das Verbot widersprüchlichen Verhaltens; for a compara­ tive analysis, see Vaquer, ‘Verwirkung versus Laches’.

69BGHZ 34, 355.