Plenty of rights, under European air travel compensation rules (EC Regulation 261/2004, which apply to flights booked on an EU airline or departing or arriving at an EU airport).
You can choose to receive a full refund or a rescheduled flight later.
What happens if I am stranded abroad?
You are entitled to receive meals and refreshments, |two telephone calls, emails, and hotel accommodation. You should also receive transport between the airport and the hotel. There is no time restriction on these benefits.
Will I be able to claim some sort of compensation?
No. Usually, you are entitled to compensation of between £220 and £520 for long delays or cancellations, but not for problems “caused by extraordinary circumstances that could not have been avoided by any reasonable measure”. The Air Transport Users Council considers that the volcanic eruption meets the definition of “extraordinary circumstances”.
Can I claim from my insurance company?
This will depend on the policy and, probably more importantly, the insurer's attitude. In general, most standard policies do not cover the ash cloud.