This is pretty much the scenario dealt with robustly by a stipendary Magistrate and the conviction upheld by the Court of Appeal in the Corbyn case (1978).
Intent to pay ONLY if challenged is an intention not to pay if not challenged.
Exactly so!
We could even go further, and confidently say that 'intent to pay ONLY if or when challenged is an intention not to pay - full stop'. For the purposes of bringing forward a prosecution, we don't need to speculate about the circumstances in which the passenger is not challenged, unless we are looking at the passenger's regular and repeated travel without ticket and without challenge, and seeking to recover the lost revenue from those journeys. Costs and lost revenue have been recovered through the Courts from passengers, some of whose journeys were both unpaid
and unchallenged.
There is some disagreement about what the "first available opportunity" is and . . . .
Indeed there is. But a lack of clear definition doesn't leave us in a hopeless position - we have no difficulty in knowing what "first available opportunity" does
NOT mean (in the context of buying a ticket before boarding a train). And when cases are being considered for prosecution, then it is those where a significant "opportunity" will NOT have been taken, whatever the details of the circumstances might be, that will be advanced.
Additionally, it clearly does NOT mean any of the excuses or complaints that passengers offer every day when asked about their non-existent ticket, no matter how forcefully they are argued, nor how carefully they are constructed and explained in hindsight; those passengers have passed at least one opportunity to do that one important thing required of them: to buy a ticket.
For those who might seek absolute definitions, I can only say that these definitions may not be as helpful as you might think: please consider other concepts which carry forceful legal obligations but are not defined, such as Negligence. We don't need a definition of the degree of care and attention required of us, but it becomes very clear when someone
has been negligent, and the illustrations in Case Law are all we need to secure convictions after the event. It is after the event that the person's failings become most apparent (as it is with rail fare avoidance).
