Paddington getting ticket gates
Ticket gates are now being installed at Paddington station to wall off most of the suburban platforms and resolve the lack of full gating on the mainline platforms. They should come into use in the next month or two, hopefully coinciding with the extension of Oyster PAYG.
The current setup is fairly interesting. Platforms 2-5 are gated at the concourse end, but the footbridge halfway along allows free access from the ungated platforms. Similarly, the gates on the footbridge for the Hammersmith & City Line (15-16) also include platforms 13-14, which are ungated at the concourse end, again making it easy to slip behind them.
The plan is to put a new gateline across the north side of the concourse (pictured) to enclose platforms 10-16, and move the H&C gateline along the footbridge to match. New gates on the footbridge will properly close off 2-5 (this diagram from the planning application should make everything clear).
Of the remaining platforms 1 is used for access and essentially ungateable; 6 and 7 are dedicated to Heathrow Express; leaving only 8-9 conspicuously ungated.
[diagram via uk.railway]