In principle, the boards always refuse requests for referral where there is no contradictory case law and they see no reason for departing from earlier decisions (see e.g. T 170/83, OJ 1984, 605; T 162/85, T 58/87, T 5/89, T 315/89, T 37/90, T 323/90, T 688/90, T 506/91, J 47/92, OJ 1995, 180; T 473/92, T 952/92 and T 702/93).
There is in principle no contradiction where a different application of the same rule is justified by different circumstances (T 143/91).
According to T 373/87 there is no contradictory case law where a single, unconfirmed decision departs from the case law established by several decisions.
The board in T 154/04 (OJ 2008, 46) found that a decision deviating from an opinion given in another decision of a board of appeal, a diverging opinion expressed in decisions of different boards, or a deviation from some national jurisprudence -- for example, from the UK case law of the Court of Appeal to which the appellant referred in support of its case -- are not per se valid reasons for referral under Art. 112(1)(a) EPC 1973 (see also Art. 15 RPBA 2003).
The legal system of the EPC allowed for the evolution of the case law and left it to the discretion of the boards whether to give reasons in any decision deviating from other decisions or to refer a point of law to the Enlarged Board. The President of the EPO could intervene under Art. 112(1)(b) EPC 1973, in particular if the legal situation became unclear for first instance proceedings.
In the interest of the harmonisation of national and international rules of law, the boards of appeal will take into consideration decisions and opinions given by national courts in interpreting the law (see G 5/83, OJ 1985, 64). Nevertheless, in the proceedings before the EPO, such considerations do not exonerate a board of appeal from its duty as an independent judicial body to interpret and apply the EPC and to decide in last instance in patent granting matters. In addition, despite harmonised legal regulations, it is not self-evident that their interpretation is also harmonised among different national courts, let alone courts of different contracting states, so that the boards of appeal would be at a loss as to which interpretation to follow if they did not exercise their own independent judgment.