It could go either way. From a legal standpoint its very clear that there is no liability in the UK on Shell's part. That being said, courts in the UK have recently rediscovered the concept of Universal Jurisdiction, which means the UK has jurisdiction for anything that happens anywhere at any time, and have been using that to gain jurisdiction over politically sensitive cases. This is a politically sensitive case.

As far as whether they will win or not, the answer is who knows. Again, UK courts have become quite political on cases like this. Again, legally speaking there appears to be very little liability on Shell Nigeria since the nearly every, if not every spill in question was the results on locals drilling into the pipelines. But with political cases like this you never really know.

However, assuming the Plaintiffs do win an award Shell will likely end up paying little, if any of it. That's not to say the Plaintiffs won't collect - they will - but the entity they are arguing caused the spills isn't Shell but Shell Nigeria.

Shell Nigeria is separate from Shell, which owns a minority interest in it. The majority controller in Shell Nigeria is the Nigerian government, which also exercises substantial control over Shell Nigeria's day to day operations. Because of this, Shell either already has an agreement in place whereby the Nigerian government will indemnify it against any damages from cases like this, or if no such agreement is in place, Shell will end up suing the Nigerian government. Because of this its very likely that Shell will ultimately recoup most, if not all, of any potential award against them from Nigeria.