The UK Parliament is currently playing ping-pong between the Lords and the Commons over a Brexit enabling act. Meanwhile Brexit pre-negotiations are already turning into a mess, with the EU demanding that the UK accept freedom of movement as a condition of market entry, and Theresa May threatening to walk away from a "bad" deal (i.e. one which doesn't let her have a racist immigration policy). Faced with the very real prospect of being stuck in a lifeboat with cannibalistic England, the Scottish government has taken the obvious course, and has demanded another independence referendum:
Nicola Sturgeon has triggered a fresh constitutional battle over Scotland’s future after announcing plans to stage a second independence referendum within two years.
Accusing Theresa May of thwarting Scotland’s desire for a special deal with Europe, the first minister confirmed she plans to hold the vote between autumn 2018 and spring 2019 unless the UK government offers substantial last-minute concessions.
Sturgeon said the prime minister’s refusal to discuss full Scottish access to the single market and to threaten heavy restrictions on the new powers for Scotland after Brexit made a second referendum all but inevitable.
The latter is particularly important - Westminster is trying to use Brexit to undermine Scotland's autonomy and seize back devolved powers. And faced with that sort of bullshit, who wouldn't leave? Better to be master of your own destiny than slave to London.
There will now be the usual fight about whether Scotland is "allowed" to have a referendum (of course they are, and it would be unconstitutional for Westminster to refuse), and about timing. Westminster will of course fight tooth and nail on them - and in the process they'll probably make the case for independence even stronger. Because every time some Westminster Tory says "no", or sneers at the idea of an independent Scotland, they make it clearer and clearer what this is about: respect. London does not respect other parts of the UK and treats them as peasants. Fortunately, Scotland is in a position to actually do something about it and leave.