There is no 351 route. But that bald statement is rather an oversimplification as there used to be one up in Essex, and, until 2002, another around Penge and Bromley as you can discover here.
Meanwhile, I wanted to say a few words in praise of Oyster Cards.
I don’t know of many other examples of people setting out to spend almost double the normal price on an identical item. Marmite in a Harrods bag?
But Linda and I, on our three buses yesterday, watched two people pay £2.30 for something that costs £1.35, because they did not have an oyster card. Yes, you pay a £5.00 deposit, but you get this back when you return it. It is strangely difficult to find any information about returning oyster cards on the TfL website, but the fact is that you can return it at any underground station ticket office. This is all very clearly set out at this address.
Before anyone comments on the fact that we freedom pass users are sheltered from all this, allow me make that comment myself.
Now. Speaking as a conspiracy theorist of long standing (ask me who killed JFK, rather than just where I was when I heard the news) I know that Oyster cards are tracked, especially if they are registered, and some people resent the totalitarian implications Here’s a summary of the dangers. On the other hand, people: £2.00 instead of £4.30 for a Zone 1 Tube journey?
Also, if you ever travel by bus outside London, you will know how long a journey can take when people have to pay their fares, collect their tickets and retrieve their change before the bus can leave each stop.