In message
, at
15:40:42 on Sat, 1 Oct 2011, Francis Davey remarked:
What I wasn't sure about is if + allows you to start (or end) at an
underground station. Ie. for the last leg of the journey to be made by
underground (at least in theory - of course I'd probably just use my
oyster for this bit).

How does one deduce that the Victoria Line is "permitted"?

This was explained in the old "Part A" of the Fares Manual, not to be
confused with Section A of the Routing Guide!

http://www.atoc.org/about-atoc/rail-...routeing-guide

The old Part A is also not supplied with the CD-ROM "Avantix Traveller"
available for a tenner from HMSO. I've not found any evidence that it's
online at all at the moment, but presumably ticket sellers have access
to it in some form. The friendliest ticket seller I found was the one at
Meldreth station (but be quick, there are plans to turn it, and many
similar, into unmanned stations).

Anyway, here's an extract from Part A of Jan 2008 (NFM98 for the geeks)
which was the last published in that form online, afaict.

"Ticket prices in Section C, for journeys routed for travel ’via
London’ and marked with the symbol + include the cost of
transfer across London by London Underground, DLR or First
Capital Connect train services on the Thameslink route. Tickets
displaying the ’cross-London’ marker â€*, are valid for travel
between any two of the following stations appropriate to the
route of the through rail journey being made.

Aldgate Finsbury Park Queens Park
Amersham Greenwich Richmond
Baker Street Highbury & Islington Seven Sisters
Balham Kensington Olympia Southwark
Bank Kentish Town Stratford
Barking King’s Cross/St Tottenham Hale
Pancras
Blackfriars Lancaster Gate Tower Hill
Blackhorse Road Lewisham Upminster
Cannon Street Limehouse Vauxhall
Charing Cross Liverpool Street Victoria
Ealing Broadway London Bridge Walthamstow Ctl
Edgware Road Marylebone Waterloo
Elephant & Castle Moorgate West Brompton
Embankment New Cross Gate West Ham
Euston Old Street West Hampstead
Euston Square Paddington Wimbledon
Farringdon

Am I right in thinking that because there's a ticket via CBG it must
be "Any Permitted"?

There are two options from Finsbury Park to Cambridge: +London[1] and
Not-London. Any Permitted just means you can use either/both. The "Not
London" is also sold separately, of course.

[1] Where the + means "including underground transfers.
--
Roland Perry