http://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWHC/Comm/2015/3532.html&query=ashot&method=boolean

One of the issues in this case was which law governed the issue of whether a party which was not a signatory to the arbitration agreement is entitled, or bound, to be a party to the arbitration. The example was given of whether a victim can be a party to an arbitration between a tortfeasor and its insurer, although this case concerned a provision of the Russian Civil Code which made one of the respondents liable in respect of the contractual obligations of its dependent company (the latter having entered into an arbitration agreement with the claimant).

Burton J held that although the question of who is a party to the arbitration agreement is governed by English law where the arbitration agreement is subject to English law (ie the substantive, rather than procedural, law of the arbitration), a different question arises where the question is whether there is jurisdiction over a non-signatory to the arbitration agreement. In such a situation, English conflicts rules will or may address another system of law. So, here, Russian law would determine the issue of whether the respondent in question could be joined to the arbitration.