I thought it was 4 hours+
Stand to be corrected. Source of information would be good.
This is covered by the following regulation
Regulation (EC) No 261/2004 of the European Parliament and of the Council of 11 February 2004 establishing common rules on compensation and assistance to passengers in the event of denied boarding and of cancellation or long delay of flights, and repealing Regulation (EEC) No 295/91
The relevant details are listed below
Article 6
Delay
1. When an operating air carrier reasonably expects a flight to be delayed beyond its scheduled time of departure:
(a) for two hours or more in the case of flights of 1500 kilometres or less; or
(b) for three hours or more in the case of all intra-Community flights of more than 1500 kilometres and of all other flights between 1500 and 3500 kilometres; or
(c) for four hours or more in the case of all flights not falling under (a) or (b),
passengers shall be offered by the operating air carrier:
(i) the assistance specified in Article 9(1)(a) and 9(2); and
(ii) when the reasonably expected time of departure is at least the day after the time of departure previously announced, the assistance specified in Article 9(1)(b) and 9(1)(c); and
(iii) when the delay is at least five hours, the assistance specified in Article 8(1)(a).
2. In any event, the assistance shall be offered within the time limits set out above with respect to each distance bracket.
And the assistance offered should be
Article 8
Right to reimbursement or re-routing
1. Where reference is made to this Article, passengers shall be offered the choice between:
(a) - reimbursement within seven days, by the means provided for in Article 7(3), of the full cost of the ticket at the price at which it was bought, for the part or parts of the journey not made, and for the part or parts already made if the flight is no longer serving any purpose in relation to the passenger's original travel plan, together with, when relevant,
- a return flight to the first point of departure, at the earliest opportunity;
(b) re-routing, under comparable transport conditions, to their final destination at the earliest opportunity; or
(c) re-routing, under comparable transport conditions, to their final destination at a later date at the passenger's convenience, subject to availability of seats.
2. Paragraph 1(a) shall also apply to passengers whose flights form part of a package, except for the right to reimbursement where such right arises under Directive 90/314/EEC.
3. When, in the case where a town, city or region is served by several airports, an operating air carrier offers a passenger a flight to an airport alternative to that for which the booking was made, the operating air carrier shall bear the cost of transferring the passenger from that alternative airport either to that for which the booking was made, or to another close-by destination agreed with the passenger.
Article 9
Right to care
1. Where reference is made to this Article, passengers shall be offered free of charge:
(a) meals and refreshments in a reasonable relation to the waiting time;
(b) hotel accommodation in cases
- where a stay of one or more nights becomes necessary, or
- where a stay additional to that intended by the passenger becomes necessary;
(c) transport between the airport and place of accommodation (hotel or other).
2. In addition, passengers shall be offered free of charge two telephone calls, telex or fax messages, or e-mails.
3. In applying this Article, the operating air carrier shall pay particular attention to the needs of persons with reduced mobility and any persons accompanying them, as well as to the needs of unaccompanied children.