Update 28 December 2018 the Court of Appeal in  EWCA Civ 2748 has confirmed. Rome I issues no longer featured in the analysis.
Update 10 November 2017:  UKEAT 0056_17_1011: The Appeals Tribunal has confirmed.
Thank you Steve Peers for alerting me to the relevance of the conflict of laws and the Rome I Regulation in particular in the recent Aslam et al v Uber Employment Tribunal decision. The case essentially revolves around whether claimants are employees – it is a pivotal case determining the immediate regulatory context for this part of the ‘sharing economy’. Para 87 is a particularly delightful expression of scepticism towards the sharing economy’s claims (further highlights are here).
Conflict of laws is addressed at para 103 onwards, a completion of the analysis in case of rejection of the tribunal’s view that the UK company in the Uber group employs claimants, and instead one would have to regard Uber BV (of The Netherlands) as employer. I do not think the tribunal expresses itself entirely clearly on Rome I.
If Uber BV is the employer, reclassification of the contract as one of employment (as opposed to one for the provision of services), makes the choice of law for Dutch law partially inoperable (not, as the tribunal notes at para 105 in fine, replaced with the laws on England and Wales). Next the tribunal (paras 106-109) continues to speak of ’employer’ but reviews application of Article 3 (including the application of Article 3(3)’s ‘purely domestic contracts’. If there is a contract of employment, in my view only Article 3(1) and (2) can have any impact on the analysis: the remainder of Article 3 concerns provisions for which Article 8 itself provides exhaustive rules.
From para 110 onwards, the tribunal does more tidily address Article 8 Rome I and holds, after reference to counsel view, that if indeed the Dutch BV is the employer (for it does not suggest that the contract would have to be qualified as one of services), Dutch law would largely apply, except for a limited number of provisions of English law by way of mandatory rules. (Reference to Article 21’s ordre public is justifiably rejected).
I am assuming Uber are appealing. Expect the conflicts analysis to return.
(Handbook of) European private international law, Chapter 3, Heading 3.2.5.