London revisited - or not

In Britain Under Steam, many companies will try to build routes to London. This could become a source of contention. A company with an existing route may upgrade one of the hexes adjacent to London purely to prevent a rival from gaining a route through. In many games I enjoy such blocking play, but in this particular case I want to allow many routes through.

So I'm considering giving each company a special token, which they trade in whenever they lay or upgrade a tile adjacent to London. This would make it harder to block a rival (although not necessarily impossible). An obvious extension would be to let one private company have a token too, so that the owning public company gets a second London build.

Some companies won't run to London at all, so I could introduce other hexes where this limit applies. The hex between Edinburgh and Glasgow might be worth considering.

An alternative approach would simply be to impose a financial cost for building in these hexes. Then any company may build extra routes or lay blocking tiles but only if they deem it worth the expenditure. Currently I prefer the token option, but I'll see what happens in play.