On the basis of the information presented on here, and a little research on my part, then it appears to me that Megatrain are operating entirely within the terms agreed when their (exceptionally cheap) tickets are offered.At your own risk. I do not advise it and cannot support it.
I also refer you to OwlMan's postThat last point seems to have been
The contract allows for cancellation if and only if the specified circumstances apply. None of the reasons in the contract that can be given for legitimate cancellation apply here, since there is no "force majeure" here- there is nothing "beyond Megabus's control".
The cheapness of the ticket is of absolutely no relevance whatsoever.
In addition, the Unfair Terms in Consumer Contracts Regulations 1999 specifically prohibit terms in consumer contracts giving the business a unilateral cancellation right without good reason.
http://www.legislation.gov.uk/uksi/1999/2083/schedule/2/made
1. Terms which have the object or effect of–
(c) making an agreement binding on the consumer whereas provision of services by the seller or supplier is subject to a condition whose realisation depends on his own will alone;
(f) authorising the seller or supplier to dissolve the contract on a discretionary basis where the same facility is not granted to the consumer, or permitting the seller or supplier to retain the sums paid for services not yet supplied by him where it is the seller or supplier himself who dissolves the contract
(n) limiting the seller’s or supplier’s obligation to respect commitments undertaken by his agents or making his commitments subject to compliance with a particular formality;
Whilst the UTCCR do not apply to contractual terms that reflect statutory or regulatory provisions (arguably including the NRCoC and the respective franchise agreements), there is nothing in the NRCoC or, to the best of my knowledge, the franchise agreements, which permits or mandates unilateral termination of contract without justification.
Based on the information stated I am absolutely certain that Megabus and/or SWT are in breach of contract, and would happily bet my life savings that a civil claim by the OP against Megabus/ SWT, if properly presented, would succeed.
Condition 1 of the NRCoC states:
http://www.nationalrail.co.uk/times_fares/nrcc/NRCOC.pdf
1. Your contract
A ticket that has been issued to you is evidence of a contract between you and each Train Company whose trains you have the right to use. Where the company selling you the ticket is not one of the Train Companies on whose services you are travelling, the seller is acting as agent for the Train Company or Companies in whose trains you are entitled to travel.
Based on the above, it appears that Megabus are acting as agents of South West Trains in selling the ticket, and the contract has actually been entered into with South West Trains. The Megabus website claims that the contract for travel is governed by the NRCoC, as amended by its own T&Cs.
I would very strongly advise bringing such a claim, if all other avenues (such as internal complaints/ Passenger Focus/ media) fail.